和自己的比起來，感覺大牛的代碼要精悍的多啊。
代碼如下：
#include <stdio.h>
#include <string.h>
#define maxn 250
struct Map
{
?int f;
?int c;
}map[maxn][maxn];
int pre[maxn];
int q[maxn*maxn];
int v[maxn];
int N,M;
int s,t;
int abs( int x ){ return x > 0 ? x : -x ; }
int min( int x, int y ){ return? x < y ? x : y; }
void init()
{
?int i, S, E, C;
?memset( map, 0, sizeof(map) );
?for(i=0;i<N;i++)
?{
??scanf( "%d%d%d", &S, &E, &C );
??map[S][E].c += C;
?}?
}
void solve()
{
?int i,j;
?int head,tail;
?s = 1;
?t = M;
?while(true)
?{
??memset( pre, 0, sizeof(pre) );
??head = 0, tail = 1;
??q[0] = s;
??v[s] = 1000000000;
??pre[s] = s;
??while( head < tail && pre[t] == 0 )
??{
???i = q[head];
???for( j = 1; j <= M; j++ )
???{
????if( pre[j] == 0 )
????{
?????if( map[i][j].f < map[i][j].c )
??????pre[j] = i , q[tail++] = j , v[j] = min( v[i], map[i][j].c-map[i][j].f );
?????else if( map[j][i].f > 0 )
??????pre[j] = -i, q[tail++] = j , v[j] = min( v[i], map[j][i].f );
????}
??????????? }
???head++;
??}
??if( pre[t] == 0 )break;
??i = t;
??while( i != s )
??{
???j = abs( pre[i] );
???if( pre[i] > 0 )map[j][i].f += v[t];
???else map[i][j].f -= v[t];
???i = j;
??}
?}
?int ans = 0;
?for( i = 1; i <= M; i++ )ans += map[s][i].f;
?printf("%d\n",ans);
}
int main()
{
?while(scanf("%d%d",&N,&M)!=EOF)
?{
??init();
??solve();
?}
?return 0;
}