HDU 4972 A simple dynamic programming problem
题意:篮球比赛有1、2、3分球 现给出两队的分差序列(5:3 分差2 3:5分差也是2) 问有多少种可能的比分
思路:
比较简单的想法题 可以类一张表“从分差x到分差y一共有几种情况” 很容易发现只有1->2和2->1的时候会多一种情况 其他均是一种 所以只需要统计这种特殊分差即可 注意一下最后结果要不要乘2 如果最后分差是0就不用因为x:x只有一种 但是最后分差不是0就要乘 因为x:y和y:x算两种 还有本题有坑!! 那个SB记分员会把分数记错 所以一旦记错种类数就为0了
代码:
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> using namespace std; int a[100010]; int main() { int t,n,i,l,flag,cas=1; scanf("%d",&t); while(t--) { scanf("%d",&n); for(i=1;i<=n;i++) scanf("%d",&a[i]); a[0]=0; l=1; flag=1; for(i=1;i<=n;i++) { if(abs(a[i]-a[i-1])>3||(a[i]!=1&&a[i]==a[i-1])) { flag=0; break; } if(a[i-1]==1&&a[i]==2||a[i-1]==2&&a[i]==1) l++; } printf("Case #%d: ",cas++); if(!flag) { printf("0\n"); } else { if(a[n]==0) printf("%d\n",l); else printf("%d\n",l*2); } } return 0; }
HDU 4973 A simple simulation problem
题意:一段区间一开始是1、2、3…n 有m个操作 D操作为区间复制 Q为查询区间最多的相同元素个数
思路:
一看就是线段树… 由于区间会复制 所以自然会想到节点记得是元素个数 比较有意思的是寻找区间方式和以往不同 不过既然已经记录了元素个数 我们就可以按个数来寻找了 我是用(head,num)表示该区间从第head个元素开始操作num个元素 这样就可以实现在线段树上找区间了 注意的是叶子节点特殊处理一下就好
代码:
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; typedef __int64 LL; #define N 50010 #define L(x) (x<<1) #define R(x) ((x<<1)|1) struct node { LL sum,max,lazy; bool leaf; }f[N*4]; int t,n,m; void up(int i) { f[i].sum=f[L(i)].sum+f[R(i)].sum; f[i].max=max(f[L(i)].max,f[R(i)].max); } void down(int i) { if(f[i].lazy!=1) { f[L(i)].sum*=f[i].lazy; f[L(i)].max*=f[i].lazy; f[L(i)].lazy*=f[i].lazy; f[R(i)].sum*=f[i].lazy; f[R(i)].max*=f[i].lazy; f[R(i)].lazy*=f[i].lazy; f[i].lazy=1; } } void init(int l,int r,int i) { f[i].leaf=false; f[i].lazy=1; if(l==r) { f[i].leaf=true; f[i].sum=f[i].max=1; return ; } int mid=(l+r)>>1; init(l,mid,L(i)); init(mid+1,r,R(i)); up(i); } void update(LL head,LL num,int i) { if(head==1&&num==f[i].sum) { f[i].sum*=2; f[i].max*=2; f[i].lazy*=2; return ; } if(f[i].leaf) { f[i].sum+=num; f[i].max+=num; return ; } down(i); if(f[L(i)].sum>=head+num-1) update(head,num,L(i)); else if(head>f[L(i)].sum) update(head-f[L(i)].sum,num,R(i)); else { LL fzc=f[L(i)].sum-head+1; update(head,fzc,L(i)); update(1,num-fzc,R(i)); } up(i); } LL query(LL head,LL num,int i) { if(head==1&&num==f[i].sum) return f[i].max; if(f[i].leaf) return num; down(i); LL res; if(f[L(i)].sum>=head+num-1) res=query(head,num,L(i)); else if(head>f[L(i)].sum) res=query(head-f[L(i)].sum,num,R(i)); else { LL fzc=f[L(i)].sum-head+1; res=query(head,fzc,L(i)); res=max(res,query(1,num-fzc,R(i))); } up(i); return res; } int main() { int i,cas=1; LL l,r; char op[3]; scanf("%d",&t); while(t--) { printf("Case #%d:\n",cas++); scanf("%d%d",&n,&m); init(1,n,1); while(m--) { scanf("%s%I64d%I64d",op,&l,&r); if(op[0]=='D') update(l,r-l+1,1); else printf("%I64d\n",query(l,r-l+1,1)); } } return 0; }
HDU 4974 A simple water problem
题意:你可以每次选1个或2个元素使它们+1 问 最少几次操作能从全0加到给出的序列
思路:
一开始一定2个加一次 如果最后只剩下一个就只能1个加一次 所以特判一下最大的元素会不会超过其他元素的和
代码:
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; typedef __int64 LL; LL a,b,c,ans; int T,t,n; int main() { int i; scanf("%d",&T); for(t=1;t<=T;t++) { scanf("%d",&n); a=b=c=0; for(i=1;i<=n;i++) { scanf("%I64d",&a); c=max(c,a); b+=a; } a=b-c; if(c>=a) ans=c; else { ans=b/2; if(ans*2<b) ans++; } printf("Case #%d: %I64d\n",t,ans); } return 0; }
HDU 4975 这是个错题… 题意就是HDU 4888
思路:
这题标程的搜索就是错的 错误的方式可以用HDU 4888的数据来hack 说一下怎么解决错题 - -b 要么你和它一样错… 要么就是你网络流跑的快一点 为暴搜留出时间 这样兴许可以搜过去!!
代码:(我写的是和它一样错的… 只要是错的代码 跑的比标程都快… 建议本题别做!!)
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int MAXN = 1010; const int MAXM = 1010 * 1010 * 2; const int INF = 2000000000; struct Node { int from, to, next, cap; } edge[MAXM]; int tol, n; int head[MAXN], dep[MAXN], gap[MAXN], sumx[MAXN], sumy[MAXN], vis[MAXN]; void addedge(int u, int v, int w) { edge[tol].from = u; edge[tol].to = v; edge[tol].cap = w; edge[tol].next = head[u]; head[u] = tol++; edge[tol].from = v; edge[tol].to = u; edge[tol].cap = 0; edge[tol].next = head[v]; head[v] = tol++; } int que[MAXN]; void BFS(int start, int end) { memset(dep, -1, sizeof(dep)); memset(gap, 0, sizeof(gap)); gap[0] = 1; int front, rear, u, v, i; front = rear = 0; dep[end] = 0; que[rear++] = end; while (front != rear) { u = que[front++]; for (i = head[u]; i != -1; i = edge[i].next) { v = edge[i].to; if (dep[v] != -1) continue; que[rear++] = v; dep[v] = dep[u] + 1; ++gap[dep[v]]; } } } int cur[MAXN], S[MAXN]; int SAP(int start, int end) { int i, u, res = 0, top = 0, temp, inser; BFS(start, end); memcpy(cur, head, sizeof(head)); u = start; while (dep[start] < n) { if (u == end) { temp = INF; for (i = 0; i < top; i++) if (temp > edge[S[i]].cap) { temp = edge[S[i]].cap; inser = i; } for (i = 0; i < top; i++) { edge[S[i]].cap -= temp; edge[S[i] ^ 1].cap += temp; } res += temp; top = inser; u = edge[S[top]].from; } if (u != end && gap[dep[u] - 1] == 0) break; for (i = cur[u]; i != -1; i = edge[i].next) if (edge[i].cap != 0 && dep[u] == dep[edge[i].to] + 1) break; if (i != -1) { cur[u] = i; S[top++] = i; u = edge[i].to; } else { int min = n; for (i = head[u]; i != -1; i = edge[i].next) { if (edge[i].cap == 0) continue; if (min > dep[edge[i].to]) { min = dep[edge[i].to]; cur[u] = i; } } --gap[dep[u]]; dep[u] = min + 1; ++gap[dep[u]]; if (u != start) u = edge[S[--top]].from; } } return res; } bool sol(int u, int fa) { int i, v; vis[u] = 1; for (i = head[u]; ~i; i = edge[i].next) { v = edge[i].to; if (!edge[i].cap || v == fa || vis[v] == 2) continue; if (vis[v] == 1 || sol(v, u)) return true; } vis[u] = 2; return false; } bool findcircle(int fn) { for (int i = 1; i <= fn; i++) { vis[i] = 1; if (sol(i, i)) return true; vis[i] = 2; } return false; } int main() { //freopen("1005.in", "r", stdin); //freopen("1005.txt", "w", stdout); int i, j, n1, n2, ans, End, CAS, fff = 1; scanf("%d", &CAS); while (CAS--) { scanf("%d%d", &n1, &n2); sumx[0] = sumy[0] = 0; for (i = 1; i <= n1; i++) { scanf("%d", &sumx[i]); sumx[0] += sumx[i]; } for (i = 1; i <= n2; i++) { scanf("%d", &sumy[i]); sumy[0] += sumy[i]; } if (sumx[0] != sumy[0]) { printf("Case #%d: So naive!\n", fff++); continue; } End = n1 + n2 + 1; tol = 0; n = End + 1; for (i = 0; i < n; i++) { head[i] = -1; vis[i] = 0; } for (i = 1; i <= n1; i++) { addedge(0, i, sumx[i]); for (j = 1; j <= n2; j++) addedge(i, n1 + j, 9); } for (i = 1; i <= n2; i++) addedge(n1 + i, End, sumy[i]); ans = SAP(0, End); if (ans != sumx[0]) printf("Case #%d: So naive!\n", fff++); else { if (findcircle(n1)) printf("Case #%d: So young!\n", fff++); else printf("Case #%d: So simple!\n", fff++); } } return 0; }