Max Flow

Max Flow imprement with scaling algorithm O(nmlgU)

#include<stdio.h>
#include<algorithm>
#include<vector>
#define INF 2000000000
using namespace std;
struct Edge
{
	int v,w,u;
};
vector<Edge*> E[1005];
int ch[1005];
Edge *root;
int T;
bool dfs(int x,int lt,int k)
{
	int a;
	if(x==lt)
		return 1;
	ch[x]=T;
	for(a=0;a<E[x].size();a++)
		if(ch[E[x][a]->w]!=T && E[x][a]->u>=k)
			if(dfs(E[x][a]->w,lt,k))
			{
				E[x][a]->u-=k;
				if((E[x][a]-root)%2)
					root[E[x][a]-root-1].u+=k;
				else
					root[E[x][a]-root+1].u+=k;
				return 1;
			}
	return 0;
}
int maxflow(int n,int m,int s,int t,Edge *edges,int *f)
{
	int a,k=0;
	bool tmp;
	root=edges;
	for(a=0;a<m;a++)
	{
		E[edges[a].v].push_back(&edges[a]);
		f[a]=edges[a].u;
		if(k<f[a])	k=f[a];
	}
	for(T=1;k>0;T++)
		if(!dfs(s,t,k))
			k/=2;	//maxflow ver. scaling algor O(nmlgU)
	for(a=0;a<m;a++)
		f[a]-=edges[a].u;
	for(a=0,k=0;a<E[t].size();a++)
		k+=E[t][a]->u;
	return k;
}