一.

二.

1.EK演算法 + SPFA 最短路

（1）程式碼：

#include <iostream>
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
const int maxn = 5000 + 7;
struct Edge{
   int from,to,next,cap,flow,cost;
}edge[maxn*20];
int head[maxn],pre[maxn],dist[maxn],n,m,tot,s,t;
bool vis[maxn];
void addEdge(int a,int b,int c,int cost){
     edge[tot].from = a;edge[tot].to = b;edge[tot].next = head[a];edge[tot].cap = c;edge[tot].flow = 0;edge[tot].cost = cost;head[a] = tot++;
     edge[tot].from = b;edge[tot].to = a;edge[tot].next = head[b];edge[tot].cap = 0;edge[tot].flow = 0;edge[tot].cost = -cost;head[b] = tot++;
}
bool SPFA(){
    memset(dist,INF,sizeof(dist));
    memset(vis,0,sizeof(vis));
    queue<int> que;
    dist[s] = 0;
    vis[s] = 1;
    que.push(s);
    while(!que.empty()){
        int u = que.front();
        que.pop();
        vis[u] = 0;
        for(int i = head[u];~i;i = edge[i].next){
            int v = edge[i].to;
            if(edge[i].cap > edge[i].flow && dist[v] > dist[u] + edge[i].cost){
                dist[v] = dist[u] + edge[i].cost;
                pre[v] = i;
                if(!vis[v]){
                    vis[v] = 1;
                    que.push(v);
                }
            }
        }
    }
    if(dist[t]!=INF)return true;
    return false;
}
int CostFlow(int &flow){
    int mincost = 0;
    while(SPFA()){
        int Min = INF;
        for(int i = t;i!=s;i = edge[pre[i]].from){
            Min = min(Min,edge[pre[i]].cap - edge[pre[i]].flow);
        }
        for(int i = t;i!=s;i = edge[pre[i]].from){
            edge[pre[i]].flow+=Min;
            edge[pre[i]^1].flow-=Min;
        }
        flow+=Min;
        mincost+=(dist[t]*Min);
    }
    return mincost;
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--){
        tot = 0;
        memset(head,-1,sizeof(head));
        scanf("%d%d%d%d",&n,&m,&s,&t);
        for(int i = 0;i<m;i++){
            int a,b,c,cost;
            scanf("%d%d%d%d",&a,&b,&c,&cost);
            addEdge(a,b,c,cost);
        }
        int MaxFlow = 0;
        int MinCost = CostFlow(MaxFlow);
        printf("%d %d\n",MaxFlow,MinCost);
    }
    return 0;
}