最大流模板

#include "stdio.h"  //最大流模板 poj 1273
#include "queue"
using namespace std;
int n,m;
#define N 205
#define INF 0x3fffffff

int map[N][N];
int maxf[N];
int route[N];

int MIN(int x,int y){	 return x<y?x:y;	}

int BFS()  //BFS找一条可行流
{
	int i;
	for(i=1;i<=n;i++)
	{
		route[i] = -1;
		maxf[i] = INF;
	}
	queue<int> q;
	q.push(1);
	int x,y;
	while(!q.empty())
	{
		x = q.front();
		q.pop();
		for(y=1;y<=n;y++)
		{
			if(route[y]==-1 && map[x][y]!=0)
			{
				route[y] = x;
				maxf[y] = MIN(maxf[x],map[x][y]);
				q.push(y);
			}
		}
	}
	if(route[n]==-1)	return 0;
	return maxf[n];
}

int EK()
{
	int ans=0,kejia;
	while(kejia = BFS())
	{
		ans += kejia;
		int x,y=n;
		while(y!=1)
		{
			x = route[y];
			map[x][y] -= kejia;
			map[y][x] += kejia;
			y = x;
		}
	}
	return ans;
}

int main()
{
	int i,j;
	int x,y,k;
	while(scanf("%d %d",&m,&n)!=-1) //m条边，n个点
	{
		memset(map,0,sizeof(map));
		while(m--)
		{
			scanf("%d %d %d",&x,&y,&k);  //从x到y的流量为k;
			map[x][y] += k;
		}
		int ans = EK();
		printf("%d
",ans);
	}
	return 0;
}

下面是用邻接表写的，提交超时！

#include "stdio.h"
#include "string.h"
#include "queue"
using namespace std;

#define N 205
#define INF 0x3fffffff

struct node{
	int u,v,w;
	int next;
}edge[2*N*10];

int n,idx;
int dis[N],route[N],head[N];

int EK();
int BFS();
void init();
int MIN(int x,int y);
void adde(int u,int v,int w);
void addedge(int u,int v,int w);

int main()
{
	int m;
	int i,j;
	int x,y,w;
	while(scanf("%d %d",&m,&n)!=-1)
	{
		init();
		while(m--)
		{
			scanf("%d %d %d",&x,&y,&w);
			adde(x,y,w);
		}
		int ans = EK();
		printf("%d
",ans);
	}
	return 0;
}

void init()
{
	idx = 0;
	memset(head,-1,sizeof(head));
}

int MIN(int x,int y){ return x<y?x:y; }

void adde(int u,int v,int w)
{
	addedge(u,v,w);
	addedge(v,u,0);
}

void addedge(int u,int v,int w)
{
	edge[idx].u = u;
	edge[idx].v = v;
	edge[idx].w = w;
	edge[idx].next = head[u];
	head[u] = idx;
	idx++;
}

int BFS()
{
	int i;
	int x,y;
	memset(route,-1,sizeof(route));
	for(i=0;i<N;i++) dis[i] = INF;
	queue<int> q;
	q.push(1);
	while(!q.empty())
	{
		x = q.front();
		q.pop();
		for(i = head[x];i!=-1;i=edge[i].next)
		{
			y = edge[i].v;
			if(route[y]==-1 && edge[i].w)
			{
				route[y] = i;
				dis[y] = MIN(dis[x],edge[i].w);
				q.push(y);
			}
		}
		if(route[n]!=-1) return dis[n];
	}
	if(route[n]==-1) return 0;
	return dis[n];
}

int EK()
{
	int ans = 0;
	int kejia;
	while(kejia = BFS())
	{
		ans += kejia;
		int x,y=route[n];
		while(y!=1 && y!=0)
		{
			x = y^1;
			edge[y].w -= kejia;
			edge[x].w += kejia;
			y = route[edge[y].u];
		}
	}
	return ans;
}