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Edmonds-Karp（EK）算法  O(V*E*E) 124ms

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
#define ll long long
#define INF 0x7FFFFFFF
#define INT_MIN -(1<<31)
#define eps 10^(-6)
#define Q_CIN ios::sync_with_stdio(false)
#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )
#define REV( i , n ) for ( int i = n - 1 ; i >= 0 ; -- i )
#define FOR( i , a , b ) for ( int i = a ; i <= b ; ++ i )
#define FOV( i , a , b ) for ( int i = a ; i >= b ; -- i )
#define CLR( a , x ) memset ( a , x , sizeof (a) )
#define RE freopen("in.txt","r",stdin)
#define WE freopen("out.txt","w",stdout)
#define NMAX 1002
#define min(a,b) ((a)>(b)?(b):(a))
#define Dian_NAX 21
int flow[Dian_NAX][Dian_NAX];   //边实际流量
int cap[Dian_NAX][Dian_NAX];    //边容量
int pre[NMAX];  //增广路径
int res[NMAX];  //残余网络int n;          //点
int EK(int s,int t)
{queueq;int ans = 0;CLR(flow,0);while(true){CLR(res,0);res[s] = INF; //源点无限大q.push(s);while(!q.empty()){int u = q.front();q.pop();for(int v=1;v<=n;v++)if(!res[v] && flow[u][v] < cap[u][v]){pre[v] = u;q.push(v);res[v] = min(res[u],cap[u][v] - flow[u][v]);}}if(res[t] == 0) //找不到增广路就退出break;for(int u = t;u != s; u=pre[u]){flow[pre[u]][u] += res[t];flow[u][pre[u]] -= res[t];      //反向边}ans += res[t];}return ans;
}
int main()
{int a,b,c,t,m;int test = 1;//  RE;scanf("%d",&t);while(t--){CLR(cap,0);scanf("%d%d",&n,&m);while(m--){scanf("%d%d%d",&a,&b,&c);cap[a][b] +=c;}printf("Case %d: %d\n",test++,EK(1,n));}return 0;
}

Dinic 124ms

#include 
#include 
#include 
using namespace std;
#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )
#define FOR( i , a , b ) for ( int i = a ; i <= b ; ++ i )
#define CLR( a , x ) memset ( a , x , sizeof (a) );
#define RE freopen("1.in","r",stdin);
#define WE freopen("output.txt","w",stdout);
#define debug(x) cout<<#x<<":"<<(x)<0){dis[i]=dis[cur]+1;q[tail++]=i;}}}if(dis[t]>0)    return 1;return 0;   //dis[t]=-1：路不通
}
//dfs为一次增广,s->t
int dfs(int s,int t,int low)//Low为增广路径上的最小流量
{int flow=0;if(s==t)    return low; //到汇点直接返回目前为止的最小流量for(int i=1;i<=n;i++){       //在下一层里找if(tab[s][i]>0&&dis[i]==dis[s]+1&&(flow=dfs(i,t,min(low,tab[s][i])))){tab[s][i]-=flow;    //不断的减流量tab[i][s]+=flow;return flow;        //能到汇点}}return 0;
}int main() {
//    REint a,b,c,t;scanf("%d",&t);for(int te=1;te<=t;te++){scanf("%d%d",&n,&m);CLR(tab,0); //流量初始化为0while(m--){scanf("%d%d%d",&a,&b,&c);tab[a][b]+=c;}int ans=0,tans=0;while(bfs(1,n))         //直到源点不能到汇点为止while(tans=dfs(1,n,0x7FFFFFFF))     //在同一个层次图里尽量找增广路ans+=tans;printf("Case %d: %d\n",te,ans);}return 0;
}

邻接表 436MS

#include 
#include 
#include 
#include 
using namespace std;
#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )
#define FOR( i , a , b ) for ( int i = a ; i <= b ; ++ i )
#define CLR( a , x ) memset ( a , x , sizeof (a) );
#define RE freopen("1.in","r",stdin);
#define WE freopen("output.txt","w",stdout);
#define debug(x) cout<<#x<<":"<<(x)<q;q.push(s);CLR(dis,-1);dis[s]=0;while(!q.empty()){int u=q.front();q.pop();for(int i=head[u];i!=-1;i=edge[i].next){int v=edge[i].v;if( dis[v]<0 && edge[i].w){dis[v]=dis[u]+1;q.push(v);}}}return dis[t]!=-1;
}
int dfs(int s,int t,int low)
{int flow;if(t==s)   return low;for(int i=head[s];i!=-1;i=edge[i].next){int v=edge[i].v;if(edge[i].w && (dis[v]==dis[s]+1) &&(flow = dfs(v,t,min(low,edge[i].w)))){edge[i].w -= flow;edge[i^1].w += flow;return flow;}}return 0;
}
int maxFlow(int s,int t)
{int ans=0,tmp;while(bfs(s,t))while(tmp=dfs(s,t,inf))ans+=tmp;return ans;
}
int main()
{int t,m,n,a,b,c;
//    REscanf("%d",&t);for(int te=1;te<=t;te++){init();scanf("%d%d",&n,&m);while(m--){scanf("%d%d%d",&a,&b,&c);addEdge(a,b,c);}printf("Case %d: %d\n",te,maxFlow(1,n));}return 0;
}