2018 German Collegiate Programming Contest (GCPC 18)
建树，求lca
代码：
#include <algorithm>
#include <iterator>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <iomanip>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define lson (l , mid , rt << 1)
#define rson (mid + 1 , r , rt << 1 | 1)
#define debug(x) cerr << #x << " = " << x << "\n";
#define pb push_back
#define pq priority_queue
typedef long long ll;
typedef unsigned long long ull;
//typedef __int128 bll;
typedef pair<ll ,ll > pll;
typedef pair<int ,int > pii;
typedef pair<int,pii> p3;
//priority_queue<int> q;//这是一个大根堆q
//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q
#define fi first
#define se second
//#define endl ‘\n‘
#define OKC ios::sync_with_stdio(false);cin.tie(0)
#define FT(A,B,C) for(int A=B;A <= C;++A) //用来压行
#define REP(i , j , k) for(int i = j ; i < k ; ++i)
#define max3(a,b,c) max(max(a,b), c);
#define min3(a,b,c) min(min(a,b), c);
//priority_queue<int ,vector<int>, greater<int> >que;
const ll mos = 0x7FFFFFFF; //2147483647
const ll nmos = 0x80000000; //-2147483648
const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f; //18
const int mod = 1e9+7;
const double esp = 1e-8;
const double PI=acos(-1.0);
const double PHI=0.61803399; //黄金分割点
const double tPHI=0.38196601;
template<typename T>
inline T read(T&x){
x=0;int f=0;char ch=getchar();
while (ch<‘0‘||ch>‘9‘) f|=(ch==‘-‘),ch=getchar();
while (ch>=‘0‘&&ch<=‘9‘) x=x*10+ch-‘0‘,ch=getchar();
return x=f?-x:x;
}
/*-----------------------showtime----------------------*/
const int maxn = 1e3+9;
string mp[maxn];
int anc[maxn*maxn][25];
int fa[maxn*maxn];
vector<int>tree[maxn*maxn];
int deep[maxn*maxn];
int vis[maxn][maxn];
int n,m;
void bfs(int sx,int sy){
queue<pii>que;
que.push(pii(sx,sy));
vis[sx][sy] = 1;
while(!que.empty()){
int x = que.front().fi,y = que.front().se;
que.pop();
int u = (x-1)*m + y;
if(y<m && mp[x][2*y] != ‘|‘){
int tx = x,ty = y+1;
if(vis[tx][ty] == 0){
vis[tx][ty] = 1;
int v = (tx-1)*m+ty;
que.push(pii(tx,ty));
tree[u].pb(v);
tree[v].pb(u);
}
}
if(y>1&&mp[x][2*y-2] != ‘|‘){
int tx = x,ty = y-1;
if(vis[tx][ty] == 0){
vis[tx][ty] = 1;
int v = (tx-1)*m+ty;
que.push(pii(tx,ty));
tree[u].pb(v);
tree[v].pb(u);
}
}
if(x>1&&mp[x-1][2*y-1] != ‘_‘){
int tx = x-1,ty = y;
if(vis[tx][ty] == 0){
vis[tx][ty] = 1;
int v = (tx-1)*m+ty;
que.push(pii(tx,ty));
tree[u].pb(v);
tree[v].pb(u);
}
}
if(x < n && mp[x][2*y-1] != ‘_‘){
int tx = x+1,ty = y;
if(vis[tx][ty] == 0){
vis[tx][ty] = 1;
int v = (tx-1)*m+ty;
que.push(pii(tx,ty));
tree[u].pb(v);
tree[v].pb(u);
}
}
}
}
void dfs(int x){
anc[x][0] = fa[x];
for(int i=1; i<=22; i++){
anc[x][i] = anc[anc[x][i-1]][i-1];
}
for(int i=0; i<tree[x].size(); i++){
if(tree[x][i]!=fa[x]){
int y = tree[x][i];
fa[y] = x;
deep[y] = deep[x]+1;
dfs(y);
}
}
}
int lca(int x,int y){
int dx = x,dy = y;
if(deep[x] < deep[y]) swap(x,y);
for(int i=22; i>=0; i--){
if(deep[y] <= deep[anc[x][i]])
x = anc[x][i];
}
int rt;
if(x==y)rt = x;
else {
for(int i=22; i>=0; i--){
if(anc[x][i] != anc[y][i]){
x = anc[x][i];
y = anc[y][i];
}
}
rt = anc[x][0];
}
return deep[dx]+deep[dy] -2* deep[rt];
}
int main(){
//scanf("%d%d", &n, &m);
cin>>n>>m;
getline(cin,mp[0]);
for(int i=0; i<=n; i++) getline(cin, mp[i]);
bfs(1,1);
dfs(1);
int q,la; ll ans = 0;
scanf("%d", &q);
for(int i=1; i<=q; i++){
int x,y;
scanf("%d%d", &x, &y);
if(i==1) la = (x-1)*m + y;
else {
int now = (x-1)*m + y;
ans += 1ll*lca(la, now);
//debug(lca(la,now));
la = now;
}
}
printf("%I64d\n", ans);
return 0;
}
求两点不经过圆内的最短路径
代码：
#include<bits/stdc++.h>
using namespace std;
#define pi acos(-1.0)
double dis(double x1, double y1, double x2, double y2) {
return sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));
}
int main() {
double x1, x2, y1, y2, ox, oy, r;
scanf("%lf %lf", &x1, &y1);
scanf("%lf %lf", &x2, &y2);
scanf("%lf %lf %lf", &ox, &oy, &r);
scanf("%lf %lf %lf", &ox, &oy, &r);
double c = dis(x1, y1, x2, y2);
double a = dis(ox, oy, x1, y1);
double b = dis(ox, oy, x2, y2);
double alpha = acos((a*a + c*c - b*b) / (2*a*c));
double beta = acos((b*b + c*c - a*a) / (2*b*c));
if(alpha > pi/2 || beta > pi/2) {
printf("%.10f\n", c);
return 0;
}
alpha = acos((a*a +b*b - c*c)/ (2*a*b));
double d = a*b*sin(alpha)/c;
if(d < r) {
double aa = acos(r/a);
double bb = acos(r/b);
alpha -= aa;
alpha -= bb;
printf("%.10f\n", sqrt(a*a - r*r) + sqrt(b*b - r*r) + alpha*r);
}
else printf("%.10f\n", c);
return 0;
}
按拓扑序转移
代码：
//#pragma GCC optimize(3)
//#pragma comment(linker, "/STACK:102400000,102400000") //c++
// #pragma GCC diagnostic error "-std=c++11"
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("-fdelete-null-pointer-checks,inline-functions-called-once,-funsafe-loop-optimizations,-fexpensive-optimizations,-foptimize-sibling-calls,-ftree-switch-conversion,-finline-small-functions,inline-small-functions,-frerun-cse-after-loop,-fhoist-adjacent-loads,-findirect-inlining,-freorder-functions,no-stack-protector,-fpartial-inlining,-fsched-interblock,-fcse-follow-jumps,-fcse-skip-blocks,-falign-functions,-fstrict-overflow,-fstrict-aliasing,-fschedule-insns2,-ftree-tail-merge,inline-functions,-fschedule-insns,-freorder-blocks,-fwhole-program,-funroll-loops,-fthread-jumps,-fcrossjumping,-fcaller-saves,-fdevirtualize,-falign-labels,-falign-loops,-falign-jumps,unroll-loops,-fsched-spec,-ffast-math,Ofast,inline,-fgcse,-fgcse-lm,-fipa-sra,-ftree-pre,-ftree-vrp,-fpeephole2",3)
#include <algorithm>
#include <iterator>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <iomanip>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define lson (l , mid , rt << 1)
#define rson (mid + 1 , r , rt << 1 | 1)
#define debug(x) cerr << #x << " = " << x << "\n";
#define pb push_back
#define pq priority_queue
typedef long long ll;
typedef unsigned long long ull;
//typedef __int128 bll;
typedef pair<ll ,ll > pll;
typedef pair<int ,int > pii;
typedef pair<int,pii> p3;
//priority_queue<int> q;//这是一个大根堆q
//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q
#define fi first
#define se second
//#define endl ‘\n‘
#define OKC ios::sync_with_stdio(false);cin.tie(0)
#define FT(A,B,C) for(int A=B;A <= C;++A) //用来压行
#define REP(i , j , k) for(int i = j ; i < k ; ++i)
#define max3(a,b,c) max(max(a,b), c);
#define min3(a,b,c) min(min(a,b), c);
//priority_queue<int ,vector<int>, greater<int> >que;
const ll mos = 0x7FFFFFFF; //2147483647
const ll nmos = 0x80000000; //-2147483648
const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f; //18
const int mod = 1e9+7;
const double esp = 1e-8;
const double PI=acos(-1.0);
const double PHI=0.61803399; //黄金分割点
const double tPHI=0.38196601;
template<typename T>
inline T read(T&x){
x=0;int f=0;char ch=getchar();
while (ch<‘0‘||ch>‘9‘) f|=(ch==‘-‘),ch=getchar();
while (ch>=‘0‘&&ch<=‘9‘) x=x*10+ch-‘0‘,ch=getchar();
return x=f?-x:x;
}
/*-----------------------showtime----------------------*/
const int maxn = 1e3+9;
vector<pii>mp[maxn];
queue<int>p,que;
int n,m;
int in[maxn];
int dp[maxn];
void topo(){
for(int i=1; i<=n; i++){
if(in[i] == 0)p.push(i);
}
while(!p.empty()){
int u = p.front();p.pop();
que.push(u);
for(int i=0; i<mp[u].size(); i++){
int v = mp[u][i].fi;
in[v]--;
if(in[v] == 0) p.push(v);
}
}
}
int main(){
scanf("%d%d", &n, &m);
for(int i=1; i<=m; i++) {
int u,v,w;
scanf("%d%d%d", &u, &v, &w);
mp[u].pb(pii(v,w));
in[v]++;
}
topo();
int mx = 0;
while(!que.empty()){
int u = que.front(); que.pop();
for(int i=0; i<mp[u].size(); i++){
int v = mp[u][i].fi,c = mp[u][i].se;
dp[v] = max(dp[v], dp[u] + c);
mx = max(mx, dp[v]);
}
}
printf("%d\n", mx);
return 0;
}
求区间交集
代码：
#include<bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;
const int maxn=3e5+10;
const int mod=1e9+10+7;
int32_t main()
{
int n; cin>>n;
int ans=1e9+10;
int l=0;
int r=1e9+10;
for(int i=1;i<=n;i++)
{
int x; cin>>x;
if(l>x)
{
cout<<0<<endl; return 0;
}
int q=x-r;
int p=x-l;
if(p>x) p=x;
if(q<0) q=0;
//cout<<q<<" "<<p<<endl;
l=q;
r=p;
ans=min(ans,r-l+1);
}
cout<<ans<<endl;
}
乘1e5再算
代码：
//#pragma GCC optimize(3)
//#pragma comment(linker, "/STACK:102400000,102400000") //c++
// #pragma GCC diagnostic error "-std=c++11"
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("-fdelete-null-pointer-checks,inline-functions-called-once,-funsafe-loop-optimizations,-fexpensive-optimizations,-foptimize-sibling-calls,-ftree-switch-conversion,-finline-small-functions,inline-small-functions,-frerun-cse-after-loop,-fhoist-adjacent-loads,-findirect-inlining,-freorder-functions,no-stack-protector,-fpartial-inlining,-fsched-interblock,-fcse-follow-jumps,-fcse-skip-blocks,-falign-functions,-fstrict-overflow,-fstrict-aliasing,-fschedule-insns2,-ftree-tail-merge,inline-functions,-fschedule-insns,-freorder-blocks,-fwhole-program,-funroll-loops,-fthread-jumps,-fcrossjumping,-fcaller-saves,-fdevirtualize,-falign-labels,-falign-loops,-falign-jumps,unroll-loops,-fsched-spec,-ffast-math,Ofast,inline,-fgcse,-fgcse-lm,-fipa-sra,-ftree-pre,-ftree-vrp,-fpeephole2",3)
#include <algorithm>
#include <iterator>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <iomanip>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define lson (l , mid , rt << 1)
#define rson (mid + 1 , r , rt << 1 | 1)
#define debug(x) cerr << #x << " = " << x << "\n";
#define pb push_back
#define pq priority_queue
typedef long long ll;
typedef unsigned long long ull;
//typedef __int128 bll;
typedef pair<ll ,ll > pll;
typedef pair<int ,int > pii;
typedef pair<int,pii> p3;
//priority_queue<int> q;//这是一个大根堆q
//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q
#define fi first
#define se second
//#define endl ‘\n‘
#define OKC ios::sync_with_stdio(false);cin.tie(0)
#define FT(A,B,C) for(int A=B;A <= C;++A) //用来压行
#define REP(i , j , k) for(int i = j ; i < k ; ++i)
#define max3(a,b,c) max(max(a,b), c);
#define min3(a,b,c) min(min(a,b), c);
//priority_queue<int ,vector<int>, greater<int> >que;
const ll mos = 0x7FFFFFFF; //2147483647
const ll nmos = 0x80000000; //-2147483648
const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f; //18
const int mod = 1e9+7;
const double esp = 1e-8;
const double PI=acos(-1.0);
const double PHI=0.61803399; //黄金分割点
const double tPHI=0.38196601;
template<typename T>
inline T read(T&x){
x=0;int f=0;char ch=getchar();
while (ch<‘0‘||ch>‘9‘) f|=(ch==‘-‘),ch=getchar();
while (ch>=‘0‘&&ch<=‘9‘) x=x*10+ch-‘0‘,ch=getchar();
return x=f?-x:x;
}
/*-----------------------showtime----------------------*/
const int maxn = 1e5;
int gcd(int a, int b){
if(b == 0)return a;
return gcd(b, a % b);
}
bool check(int x){
if(x == 1) return false;
for(int i=2; i*i <= x; i++){
if(x % i==0)return false;
}
return true;
}
int main(){
// cout<<gcd(5 ,10)<<endl;
int T; scanf("%d", &T);
double a,b;
int n,m;
while(T--){
scanf("%lf%lf", &a, &b);
a += 5e-6;
b += 5e-6;
n = (int)(a * maxn );
m = (int)(b * maxn);
//cout<<n<<" "<<m<<endl;
int q = __gcd(n, m);
n = n/q;
m = m/q;
// cout<<n<<" "<<m<<endl;
if(n == m) printf("2 2\n");
else if(check(n) && check(m)){
printf("%d %d\n", n,m);
}
else puts("impossible");
}
return 0;
}
代码：
#include<bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;
const int maxn=1e6+10;
const int mod=1e9+7;
vector<int> vs[maxn];
int32_t main()
{
int n; cin>>n;
for(int i=1;i<=n;i++)
{
int x; cin>>x; vs[x].push_back(i);
}
int l=1;
int r=1;
if(vs[1].size()>=2)
{
cout<<vs[1][0]<<" "<<vs[1][1]<<endl;
return 0;
}
while(1)
{
if(l>1e6||r>1e6)
{
break;
}
int k=l+r;
l=r;
r=k;
//cout<<l<<" "<<r<<endl;
if(vs[l].size()&&vs[r].size())
{
cout<<vs[l][0]<<" "<<vs[r][0]<<endl;
return 0;
}
}
cout<<"impossible"<<endl;
}
1^(n-1) + 2^(n-1) + ... + s^(n-1) = m
代码：
#include<bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;
const int maxn=1e6+10;
const int mod=1e9+7;
vector<int> vs[maxn];
int32_t main()
{
int n; cin>>n;
for(int i=1;i<=1e6;i++)
{
int x=i*(i+1)*(2*i+1)/6;
if(x<n)
{
continue;
}
if(n==x)
{
cout<<3<<" "<<i<<endl;
return 0;
}
if(x>n)
{
break;
}
}
for(int p=4;p<=64;p++)
{
int ans=0;
for(int i=1;i<=1e6;i++)
{
int t=1;
for(int c=1;c<p;c++)
{
t*=i;
}
ans+=t;
if(ans<n) continue;
else if(ans==n)
{
cout<<p<<" "<<i<<endl;
return 0;
}
else
{
break;
}
}
}
cout<<"impossible"<<endl;
}
代码：
//#pragma GCC optimize(3)
//#pragma comment(linker, "/STACK:102400000,102400000") //c++
// #pragma GCC diagnostic error "-std=c++11"
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("-fdelete-null-pointer-checks,inline-functions-called-once,-funsafe-loop-optimizations,-fexpensive-optimizations,-foptimize-sibling-calls,-ftree-switch-conversion,-finline-small-functions,inline-small-functions,-frerun-cse-after-loop,-fhoist-adjacent-loads,-findirect-inlining,-freorder-functions,no-stack-protector,-fpartial-inlining,-fsched-interblock,-fcse-follow-jumps,-fcse-skip-blocks,-falign-functions,-fstrict-overflow,-fstrict-aliasing,-fschedule-insns2,-ftree-tail-merge,inline-functions,-fschedule-insns,-freorder-blocks,-fwhole-program,-funroll-loops,-fthread-jumps,-fcrossjumping,-fcaller-saves,-fdevirtualize,-falign-labels,-falign-loops,-falign-jumps,unroll-loops,-fsched-spec,-ffast-math,Ofast,inline,-fgcse,-fgcse-lm,-fipa-sra,-ftree-pre,-ftree-vrp,-fpeephole2",3)
#include <algorithm>
#include <iterator>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <iomanip>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define lson (l , mid , rt << 1)
#define rson (mid + 1 , r , rt << 1 | 1)
#define debug(x) cerr << #x << " = " << x << "\n";
#define pb push_back
#define pq priority_queue
typedef long long ll;
typedef unsigned long long ull;
//typedef __int128 bll;
typedef pair<ll ,ll > pll;
typedef pair<int ,int > pii;
typedef pair<int,pii> p3;
//priority_queue<int> q;//这是一个大根堆q
//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q
#define fi first
#define se second
//#define endl ‘\n‘
#define OKC ios::sync_with_stdio(false);cin.tie(0)
#define FT(A,B,C) for(int A=B;A <= C;++A) //用来压行
#define REP(i , j , k) for(int i = j ; i < k ; ++i)
#define max3(a,b,c) max(max(a,b), c);
#define min3(a,b,c) min(min(a,b), c);
//priority_queue<int ,vector<int>, greater<int> >que;
const ll mos = 0x7FFFFFFF; //2147483647
const ll nmos = 0x80000000; //-2147483648
const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f; //18
const int mod = 1e9+7;
const double esp = 1e-8;
const double PI=acos(-1.0);
const double PHI=0.61803399; //黄金分割点
const double tPHI=0.38196601;
template<typename T>
inline T read(T&x){
x=0;int f=0;char ch=getchar();
while (ch<‘0‘||ch>‘9‘) f|=(ch==‘-‘),ch=getchar();
while (ch>=‘0‘&&ch<=‘9‘) x=x*10+ch-‘0‘,ch=getchar();
return x=f?-x:x;
}
/*-----------------------showtime----------------------*/
const int maxn = 1e3+9;
int h[maxn],v[maxn],dif[maxn];
int n;
bool check(int x){
for(int i=1; i<=n; i++){
if(dif[i] + x > 0) return true;
else if(dif[i] + x < 0)return false;
}
return true;
}
int main(){
scanf("%d", &n);
for(int i=1; i<=n; i++) scanf("%d", &h[i]);
for(int i=1; i<=n; i++) scanf("%d", &v[i]);
for(int i=1; i<=n; i++) dif[i] = h[i] - v[i];
int ans = 0;
for(int i=0; i<=maxn; i++){
if(check(i)){ans = i;break;}
}
printf("%d\n", ans);
return 0;
}
模拟
代码：
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize(4)
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pi acos(-1.0)
#define LL long long
//#define mp make_pair
#define pb push_back
#define ls rt<<1, l, m
#define rs rt<<1|1, m+1, r
#define ULL unsigned LL
#define pll pair<LL, LL>
#define pli pair<LL, int>
#define pii pair<int, int>
#define piii pair<pii, int>
#define pdd pair<long double, long double>
#define mem(a, b) memset(a, b, sizeof(a))
#define fio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fopen freopen("in.txt", "r", stdin);freopen("out.txt", "w", stout);
//head
const int N = 3e5 + 10;
int a[N][4];
int t[N*2][2];
vector<int> vc;
int main() {
int n;
scanf("%d", &n);
int st = -1;
int tmp[4];
for (int i = 1; i <= n; i++) {
for (int j = 0; j < 4; j++) {
scanf("%d", &a[i][j]);
if(a[i][j]) {
int tmp = a[i][j];
if(t[tmp][0]) t[tmp][1] = i;
else t[tmp][0] = i;
}
}
swap(a[i][0], a[i][2]);
for (int j = 0; j < 4; j++) {
if(!a[i][j] && !a[i][(j+1)%4]) st = i;
}
}
for (int j = 0; j < 4; j++) {
if(!a[st][j] && !a[st][(j+1)%4]) {
tmp[0] = tmp[1] = 0;
tmp[2] = a[st][(j+2)%4];
tmp[3] = a[st][(j+3)%4];
break;
}
}
if(~st);
else return 0*puts("impossible");
vc.pb(st);
for (int j = 0; j < 4; j++) a[st][j] = tmp[j];
while(true) {
int now = vc.back();
if(!a[now][2]) break;
int id = a[now][2];
int nx;
if(t[id][0] == now) nx = t[id][1];
else nx = t[id][0];
for (int j = 0; j < 4; j++) {
if(a[nx][j] == id) {
tmp[0] = a[nx][j];
tmp[1] = a[nx][(j+1)%4];
tmp[2] = a[nx][(j+2)%4];
tmp[3] = a[nx][(j+3)%4];
break;
}
}
for (int j = 0; j < 4; j++) a[nx][j] = tmp[j];
if(a[nx][1]) return 0*puts("impossible");
vc.pb(nx);
}
int m = (int)vc.size();
if(n%m) return 0*puts("impossible");
if(n == m) {
for (int i = 0; i < n; i++) if(a[vc[i]][3]) return 0*puts("impossible");
}
for (int i = m; i < n; i++) {
int now = vc[i-m];
if(!a[now][3]) return 0*puts("impossible");
int id= a[now][3];
int nx;
if(t[id][0] == now) nx = t[id][1];
else nx = t[id][0];
for (int j = 0; j < 4; j++) {
if(a[nx][j] == id) {
tmp[1] = a[nx][j];
tmp[2] = a[nx][(j+1)%4];
tmp[3] = a[nx][(j+2)%4];
tmp[0] = a[nx][(j+3)%4];
break;
}
}
for (int j = 0; j < 4; j++) a[nx][j] = tmp[j];
if(i%m == 0 && a[nx][0]) return 0*puts("impossible");
if(i%m == m-1 && a[nx][2]) return 0*puts("impossible");
if(i%m > 0 && (a[nx][0] != a[vc[i-1]][2] || a[nx][0] == 0)) return 0*puts("impossible");
if(i >= n-m && a[nx][3]) return 0*puts("impossible");
if(i < n-m && a[nx][3] == 0) return 0*puts("impossible");
vc.pb(nx);
}
printf("%d %d", n/m, m);
for (int i = 0; i < n; i++) {
if(i%m == 0) printf("\n");
printf("%d ", vc[i]);
}
return 0;
}
dp[i][j]:和为i且线段个数为j是否存在
代码：
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize(4)
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pi acos(-1.0)
#define LL long long
//#define mp make_pair
#define pb push_back
#define ls rt<<1, l, m
#define rs rt<<1|1, m+1, r
#define ULL unsigned LL
#define pll pair<LL, LL>
#define pli pair<LL, int>
#define pii pair<int, int>
#define piii pair<pii, int>
#define pdd pair<long double, long double>
#define mem(a, b) memset(a, b, sizeof(a))
#define fio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fopen freopen("in.txt", "r", stdin);freopen("out.txt", "w", stout);
//head
const int N = 66, M = 2e3 + 5;
const int INF = 0x3f3f3f3f;
const double eps = 5e-6;
int a[N], n, g;
bool dp[M][N];
int main() {
scanf("%d %d", &n, &g);
for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
dp[0][0] = true;
for (int i = 1; i <= n; i++) {
for (int j = M-1; j >= a[i]; j--) {
for (int k = n; k >= 1; k--) {
dp[j][k] |= dp[j-a[i]][k-1];
}
}
}
double ans = -1;
for (int j = g-10; j < M; j++) {
for (int i = 1; i <= n; i++) {
if(dp[j][i]) {
if(j+10-g <= 5*(i+1)) ans = max((j+10.0-g)/(double)(i+1), ans);
}
}
}
if(ans < -0.5) printf("impossible");
else printf("%.9f\n", ans);
return 0;
}
模拟：
代码：
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
const int N = 110;
int a[N][N];
int h, w;
bool vis[N][N];
int dir[4][2] = {0, 1, 1, 0, 0, -1, -1, 0};
int main() {
scanf("%d %d", &h, &w);
for (int i = 0; i <= h+1; i++) {
for (int j = 0; j <= w+1; j++) {
scanf("%d", &a[i][j]);
}
}
bool f = false;
for (int i = 0; i <= h+1; i++) {
for (int j = 0; j <= w+1; j++) {
int cnt = 0;
for (int ii = -1; ii <= 1; ii++) {
for (int jj = -1; jj <= 1; jj++) {
int x = i + ii;
int y = j + jj;
if(1 <= x && x <= h && 1 <= y && y <= w) {
if(vis[x][y]) cnt++;
}
}
}
int res = a[i][j] - cnt;
int x = i+1, y = j+1;
if(1 <= x && x <= h && 1 <= y && y <= w) {
if(res < 0 || res > 1) {
f = true;
break;
}
else if(res == 1){
vis[x][y] = true;
}
}
else {
if(res != 0) {
f = true;
break;
}
}
}
}
if(f) puts("impossible");
else {
for (int i = 1; i <= h; i++) {
for (int j = 1; j <= w; j++){
if(vis[i][j]) putchar(‘X‘);
else putchar(‘.‘);
}
puts("");
}
}
return 0;
}
按高度从小到大启发式合并并查集，合并并查集时更新答案为当前高度
代码：
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pi acos(-1.0)
#define y1 y11
#define pb push_back
#define pii pair<int, int>
const int N = 505, M = 1e6 + 10, MM = 1e5 + 10, NN = N*N;
int fa[NN], sz[NN];
int h[N][N], n, m;
vector<pii> vc[M];
int x1[MM], y1[MM], x2[MM], y2[MM], ans[MM];
set<int> s[NN], que[NN];
map<int, int> mp[NN];
int dir[4][2] = {1, 0, 0, 1, -1, 0, 0, -1};
void init() {
for (int i = 0; i < N*N; i++) fa[i] = i, s[i].insert(i);
}
int get_id(int x, int y) {
return (x-1)*n + y;
}
int Find(int x) {
if(x == fa[x]) return x;
else return fa[x] = Find(fa[x]);
}
void Merge(int x, int y, int h) {
x = Find(x);
y = Find(y);
if(x == y) return ;
if(s[x].size() < s[y].size()) {
fa[x] = y;
for(int a : s[x]) {
s[y].insert(a);
for (int b : que[a]) {
if(s[y].find(b) != s[y].end() && mp[a].find(b) == mp[a].end()) {
mp[a][b] = h;
mp[b][a] = h;
}
}
}
}
else {
fa[y] = x;
for(int a : s[y]) {
s[x].insert(a);
for (int b : que[a]) {
if(s[x].find(b) != s[x].end() && mp[a].find(b) == mp[a].end()) {
mp[a][b] = h;
mp[b][a] = h;
}
}
}
}
}
void solve() {
for (int i = 1; i < M; i++) {
for (pii p : vc[i]) {
int x = p.fi;
int y = p.se;
int id = get_id(x, y);
for (int j = 0; j < 4; j++) {
int xx = x + dir[j][0];
int yy = y + dir[j][1];
if(xx < 1 || xx > m || yy < 1 || yy > n) continue;
if(h[xx][yy] <= i) {
Merge(id, get_id(xx, yy), i);
}
}
}
}
}
int main() {
int q;
scanf("%d %d %d", &m, &n, &q);
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= n; j++) {
scanf("%d", &h[i][j]);
vc[h[i][j]].pb({i, j});
}
}
for (int i = 1; i <= q; i++) {
scanf("%d %d %d %d", &x1[i], &y1[i], &x2[i], &y2[i]);
if(x1[i] == x2[i] && y1[i] == y2[i]) {
ans[i] = h[x1[i]][y1[i]];
}
else {
int id1 = get_id(x1[i], y1[i]);
int id2 = get_id(x2[i], y2[i]);
que[id1].insert(id2);
que[id2].insert(id1);
}
}
init();
solve();
for (int i = 1; i <= q; i++) {
if(ans[i]) printf("%d\n", ans[i]);
else printf("%d\n", mp[get_id(x1[i], y1[i])][get_id(x2[i], y2[i])]);
}
return 0;
}
原文地址：https://www.cnblogs.com/widsom/p/10290561.html
时间： 2024-08-28 08:56:31