Codeforces Round #450 (Div. 2)
http://codeforces.com/contest/900
A
1 #include<bits/stdc++.h>
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define sqr(x) ((x)*(x))
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 100005
9 #define eps 1e-8
10 #define pi acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k<j;k++)
12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pair<long long,int>pli;
15 typedef pair<int,char> pic;
16 typedef pair<pair<int,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1e9+7;
19 /*#ifndef ONLINE_JUDGE
20 freopen("1.txt","r",stdin);
21 #endif */
22
23 int a[2];
24 int main(){
25 #ifndef ONLINE_JUDGE
26 // freopen("1.txt","r",stdin);
27 #endif
28 std::ios::sync_with_stdio(false);
29 int n;
30 cin>>n;
31 int u,v;
32 for(int i=0;i<n;i++){
33 cin>>u>>v;
34 if(u>0) a[0]++;
35 else a[1]++;
36 }
37 if(a[0]<=1||a[1]<=1) cout<<"YES"<<endl;
38 else cout<<"NO"<<endl;
39 }
B
模拟除法
1 #include<bits/stdc++.h>
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define sqr(x) ((x)*(x))
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 100005
9 #define eps 1e-8
10 #define pi acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k<j;k++)
12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pair<long long,int>pli;
15 typedef pair<int,char> pic;
16 typedef pair<pair<int,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1e9+7;
19 /*#ifndef ONLINE_JUDGE
20 freopen("1.txt","r",stdin);
21 #endif */
22
23 int a[2];
24 ll fac[15];
25 int main(){
26 #ifndef ONLINE_JUDGE
27 // freopen("1.txt","r",stdin);
28 #endif
29 int a,b,c;
30 cin>>a>>b>>c;
31 int co=1;
32 while(1){
33 a*=10;
34 int k=a/b;
35 a%=b;
36 if(k==c){
37 cout<<co<<endl;
38 return 0;
39 }
40 co++;
41 if(co>=100000) break;
42 }
43 cout<<-1<<endl;
44
45 }
C
找规律
1 #include<bits/stdc++.h>
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define sqr(x) ((x)*(x))
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 100005
9 #define eps 1e-8
10 #define pi acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k<j;k++)
12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pair<long long,int>pli;
15 typedef pair<int,char> pic;
16 typedef pair<pair<int,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1e9+7;
19 /*#ifndef ONLINE_JUDGE
20 freopen("1.txt","r",stdin);
21 #endif */
22
23 int n;
24 int a[maxn],cnt[maxn];
25
26 int main(){
27 #ifndef ONLINE_JUDGE
28 // freopen("1.txt","r",stdin);
29 #endif
30 cin>>n;
31 int max1=0,max2=0;
32 for(int i=1;i<=n;i++) cin>>a[i];
33 for(int i=1;i<=n;i++){
34 if(a[i]>max1){
35 max2=max1;
36 max1=a[i];
37 cnt[a[i]]--;
38 }
39 else if(a[i]>max2){
40 cnt[max1]++;
41 max2=a[i];
42 }
43 }
44 int max3=-maxn,ans;
45 for(int i=1;i<=n;i++){
46 if(cnt[i]>max3){
47 max3=cnt[i];
48 ans=i;
49 }
50 }
51 cout<<ans<<endl;
52
53 }
D
记忆化搜索+容斥
1 #include<bits/stdc++.h>
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define sqr(x) ((x)*(x))
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 100005
9 #define eps 1e-8
10 #define pi acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k<j;k++)
12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pair<long long,int>pli;
15 typedef pair<int,char> pic;
16 typedef pair<pair<int,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1e9+7;
19 /*#ifndef ONLINE_JUDGE
20 freopen("1.txt","r",stdin);
21 #endif */
22
23 int x,y;
24 map<int,int>mp;
25
26 ll pow_mul(ll a,ll b){
27 ll ans=1;
28 while(b){
29 if(b&1) ans=(ans*a)%MOD;
30 b>>=1;
31 a=(a*a)%MOD;
32 }
33 return ans;
34 }
35
36 ll dp(int x){
37 if(x==1) return 1;
38 if(mp.count(x)) return mp[x];
39 mp[x]=pow_mul(2,x-1);
40 for(int i=2;i*i<=x;i++){
41 if(x%i==0){
42 mp[x]=(mp[x]-dp(x/i)+MOD)%MOD;
43 if(i!=x/i){
44 mp[x]=(mp[x]-dp(i)+MOD)%MOD;
45 }
46 }
47 }
48 return mp[x]=(mp[x]-dp(1)+MOD)%MOD;
49 }
50
51 int main(){
52 #ifndef ONLINE_JUDGE
53 // freopen("1.txt","r",stdin);
54 #endif
55 cin>>x>>y;
56 if(y%x){
57 cout<<0<<endl;
58 }
59 else{
60 cout<<dp(y/x)<<endl;
61 }
62
63 }
E
DP
1 #include<bits/stdc++.h>
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define sqr(x) ((x)*(x))
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 100005
9 #define eps 1e-8
10 #define pi acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k<j;k++)
12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pair<long long,int>pli;
15 typedef pair<int,char> pic;
16 typedef pair<pair<int,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1e9+7;
19 /*#ifndef ONLINE_JUDGE
20 freopen("1.txt","r",stdin);
21 #endif */
22 pii d[maxn];
23 int f[3][maxn], n, m, b[maxn];
24 char a[maxn];
25
26 int main(){
27 #ifndef ONLINE_JUDGE
28 // freopen("1.txt","r",stdin);
29 #endif
30 cin >> n;
31 for (int i = 1; i <= n; i++)
32 cin >> a[i];
33 cin >> m;
34 for (int i = 1; i <= n; i++)
35 {
36 if (a[i] == ‘?‘)
37 b[i] = b[i-1] + 1;
38 else b[i] = b[i-1];
39 if (a[i] != ‘a‘)
40 f[1][i] = f[0][i-1]+1;
41 if (a[i] != ‘b‘)
42 f[0][i] = f[1][i-1]+1;
43 if (f[!(m&1)][i] >= m)
44 d[i] = {d[i-m].first + 1, -(b[i]-b[i-m]-d[i-m].second)};
45 d[i] = max(d[i-1], d[i]);
46 }
47 cout << - d[n].second;
48
49 }
原文地址：https://www.cnblogs.com/Fighting-sh/p/10538681.html
时间： 2024-11-06 03:47:11