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1 #include<cstdio> 2 #include<cstring> 3 #include<cstdlib> 4 #include<queue> 5 using namespace std; 6 #define N 1005 7 #define inf 9999999 8 int map[N][N],path[N],flow[N]; 9 int start,eend,ans,n,m; 10 11 int bfs(){ 12 int t,i; 13 queue<int>q; 14 while(!q.empty())q.pop(); 15 memset(path,-1,sizeof(path)); 16 path[start]=0; 17 flow[start]=inf; 18 q.push(start); 19 while(!q.empty()){ 20 t=q.front(); 21 q.pop(); 22 if(t==eend)break; 23 for(i=start;i<=eend;i++){//n 24 if(i!=start&&path[i]==-1&&map[t][i]){ 25 flow[i]=flow[t]<map[t][i]?flow[t]:map[t][i]; 26 path[i]=t; 27 q.push(i); 28 } 29 } 30 } 31 if(path[eend]!=-1)return flow[eend]; 32 else return -1; 33 } 34 void ek(){ 35 36 int now,pre,delta; 37 while((delta=bfs())!=-1){ 38 ans+=delta; 39 now=eend; 40 while(now!=start){ 41 pre=path[now]; 42 map[pre][now]-=delta; 43 map[now][pre]+=delta; 44 now=pre; 45 } 46 } 47 return ; 48 } 49 50 int main() 51 { 52 int i,j,k,tcase,t; 53 int a,b,c; 54 scanf("%d",&tcase); 55 for(t=1;t<=tcase;t++) 56 { 57 scanf("%d%d",&n,&m); 58 start=1; 59 eend=n; 60 memset(map,0,sizeof(map)); 61 while(m--) 62 { 63 scanf("%d%d%d",&a,&b,&c); 64 map[a][b]+=c; 65 } 66 ans=0; 67 ek(); 68 printf("Case %d: %d\n",t,ans); 69 } 70 return 0; 71 }
EK算法
不过还是有点不太明白，EK和Ford—fulkson算法有什么区别。。。。。。。。