怒搞一下午网络流，又去我一块心病。

从2F到SAP再到Dinic最终过掉了。

但是书上说Dinic的时间复杂度为v*v*e。感觉也应该超时的啊，但是过掉了，好诡异。

后两种算法都是在第一种的基础上进行优化。

第一种方法就是不停的寻找增广路。后两种引进了层次网络的概念。第三种又改善了寻找增广路的方法。

如今仅仅能理解到这里了。。

。

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <queue>
#include <cmath>
#include <stack>
#include <map>#pragma comment(linker, "/STACK:1024000000");
#define EPS (1e-8)
#define LL long long
#define ULL unsigned long long
#define _LL __int64
#define _INF 0x3f3f3f3f
#define Mod 6000007using namespace std;struct E
{int u,v,Max,now,next;
}edge[30000];int Top;int head[300];void Link(int u,int v,int w)
{edge[Top].u = u;edge[Top].v = v;edge[Top].Max = w;edge[Top].now = 0;edge[Top].next = head[u];head[u] = Top++;
}struct P
{int pre,now,floor;bool mark;
}sta[300];void Modify(int a,int t)
{while(t != 1){edge[sta[t].pre].now += a;t = edge[sta[t].pre].u;}
}int SAP(int s,int t,int n)
{for(int i = 1;i <= n; ++i)sta[i].mark = false;queue<int> q;q.push(s);sta[s].mark = true;sta[s].now = 2000000000;sta[s].pre = -1;while(q.empty() == false){if(sta[t].mark && sta[t].now){Modify(sta[t].now,t);return sta[t].now;}int f = q.front();q.pop();for(int p = head[f];p != -1; p = edge[p].next){if(sta[edge[p].v].mark == false && sta[edge[p].u].floor == sta[edge[p].v].floor-1 && sta[edge[p].u].floor < sta[t].floor){sta[edge[p].v].now = min(sta[f].now,edge[p].Max - edge[p].now);if(sta[edge[p].v].now == 0)continue;sta[edge[p].v].pre = p;//记录边的存储位置sta[edge[p].v].mark = true;q.push(edge[p].v);}}}return 0;
}void Updata_Floor(int s,int t,int n)
{queue<int> q;for(int i = 0;i <= n; ++i)sta[i].mark = false,sta[i].floor = n;q.push(s);sta[s].mark = true;sta[s].floor = 1;while(q.empty() == false){int f = q.front();q.pop();if(sta[t].mark && sta[t].floor <= sta[f].floor)return ;for(int p = head[f];p != -1; p = edge[p].next){if(sta[edge[p].v].mark == false && edge[p].now < edge[p].Max){sta[edge[p].v].mark = true;sta[edge[p].v].floor = sta[f].floor + 1;q.push(edge[p].v);}}}
}int dfs(int s,int t,int a)
{if(s == t)return a;int f = 0;for(int p = head[s],temp = 0;p != -1; p = edge[p].next){if((sta[edge[p].v].floor < sta[t].floor || edge[p].v == t) && sta[edge[p].v].floor == sta[s].floor+1 && edge[p].now < edge[p].Max){temp = dfs(edge[p].v,t,min(a-f,edge[p].Max-edge[p].now));edge[p].now += temp;f += temp;}}return f;
}int Dinic(int s,int t,int n)
{return dfs(s,t,200000000);
}int Cal_Max_Flow(int s,int t,int n)
{int temp,f = 0;do{Updata_Floor(s,t,n);//temp = SAP(s,t,n);temp = Dinic(s,t,n);f += temp;}while(temp);return f;
}int main()
{char s[50];int i,n,np,nc,m,u,v,w;while(scanf("%d %d %d %d",&n,&np,&nc,&m) != EOF){memset(head,-1,sizeof(head));Top = 0;for(i = 0;i < m; ++i){scanf("%s",s);sscanf(s,"(%d,%d)%d",&u,&v,&w);Link(u+2,v+2,w);}for(i = 0;i < np; ++i){scanf("%s",s);sscanf(s,"(%d)%d",&u,&w);Link(1,u+2,w);}for(i = 0;i < nc; ++i){scanf("%s",s);sscanf(s,"(%d)%d",&u,&w);Link(u+2,n+2,w);}printf("%d\n",Cal_Max_Flow(1,n+2,n+2));}return 0;
}