2268969_ac_0ms_220k.c

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <string.h>
#define MaxV 201

int n, m;
long ans, map[MaxV][MaxV];

int input()
{
	int i;
	int st, ed;
	long w;

	if(scanf("%d%d",&n,&m)!=2)
		return 0;
	ans = 0;
	memset(map,0,sizeof(map));
	for(i = 0; i < n; i++)
	{
		scanf("%d%d%ld",&st,&ed,&w);
		if(st!=ed)
			map[st-1][ed-1] += w;
	}
	return 1;
}

int bfs()
{
	int i, mark = 0;
	int f, r, p;
	int pre[MaxV], visited[MaxV];
	int queue[MaxV];
	long C, F[MaxV];

	f = r = -1;
	memset(pre,0,sizeof(pre));
	memset(visited,0,sizeof(visited));
	visited[0] = 1;queue[++f] = 0;pre[0] = -1;
	C = 2100000000;
	while(f!=r)
	{
		++r;
		p = queue[r];
		for(i = 0; i < m; i++)
			if(map[p][i]&&!visited[i])
			{
				visited[i] = 1;
				queue[++f] = i;
				pre[i] = p;
				F[i] = map[p][i];
				if(i==m-1)
				{	
					mark = 1;
					goto m1;
				}
			}
	}
	m1:;
	if(mark)
	{
		p = m-1;
		while(pre[p]!=-1)
		{
			if(F[p]<C)
				C = F[p];
			p = pre[p];
		}
		p = m-1;
		while(pre[p]!=-1)
		{
			map[pre[p]][p] -= C;
			map[p][pre[p]] += C;
			p = pre[p];
		}
		ans += C;
	}
	return mark;
}

int main()
{
	while(input())
	{
		while(bfs());
		printf("%ld\n",ans);
	}
	return 1;
}