题意:n个人比赛,得分最高的算赢了,打败了所有比自己高的分的人也算赢了,问最多有多少人赢了。。
网络流:人数很少。把每一场比赛都看作一个点。建建图;枚举答案就行了。
恶心的输入啊。。输入的每一行后面还可能有空格。再codeblocks中直接把后面的空格去掉了。。tle,wa了n多次。。。
#include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <iostream> #include <queue> #include <stack> using namespace std; const int N = 99; const int INF = 0x3f3f3f3f; int g[N][N],gap[N],dist[N],pre[N],cur[N]; int sap(int s1,int t1,int n) { int ret = 0,aug = INF,u,v; memset(gap,0,sizeof(gap)); memset(dist,0,sizeof(dist)); for(int i=0;i<=n;i++) cur[i] = 1; u = pre[s1] = s1; gap[0] = n; while(dist[s1]<=n){ loop: for(v = cur[u];v<=n;v++) if(g[u][v]>0&&dist[u] ==dist[v]+1) { cur[u] = v;aug = min(aug,g[u][v]); pre[v] = u; u = v; if(u==t1){ ret+=aug; for(u=pre[u];v!=s1;v=u,u=pre[u]) g[u][v]-=aug,g[v][u]+=aug; aug = INF; } goto loop; } int mind =n; for(v=1;v<=n;v++) if(g[u][v]>0&&mind>dist[v]) mind = dist[v],cur[u] = v; if(--gap[dist[u]]<=0) break; gap[dist[u]=mind+1]++; u=pre[u]; }return ret; } int re[19]; int n; void init() { char a[10000]; n = 1; gets(a); int len=strlen(a),tmp=0,f = 0; for(int i=0;i<=len;i++) { if(a[i]<'0'||a[i]>'9') { if(f) { re[n++] = tmp; tmp = 0;f = 0; } }else { tmp = tmp*10+a[i]-'0'; f = 1; } } } int solve() { int ans=n-1 ; re[0] = -1; sort(re+1,re+n+1); //for(ans = n-1;re[ans]==re[ans+1];ans--); while(ans>=0) { memset(g,0,sizeof(g)); int s = n+1,t = n+2; for(int i=1;i<=n;i++) g[s][i] = re[i]; int tmp = t; for(int i=1;i<=n;i++) { for(int j=i+1;j<=n;j++) { tmp++; g[tmp][t] = 1; if(i>ans&&re[j]!=re[i]) g[i][tmp] =1; else g[i][tmp] = g[j][tmp] = 1; } } if(sap(s,t,tmp)<(n*(n-1)/2)) { return n-ans-1; }ans--; } return n; } int main() { freopen("in.txt","r",stdin); int cas; scanf("%d",&cas); getchar(); while(cas--) { init();n--; // for(int i=1;i<=n;i++) cout<<re[i]<<" ";cout<<endl; printf("%d\n",solve()); } return 0; }