解题思路:裸题,但是要注意重边是叠加的。
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
int map[205][205],n,m;
int dis[205];
const int inf=0x3f3f3f3f;
queue<int> q;
int bfs()
{
while(!q.empty()) q.pop();
memset(dis,0,sizeof(dis));
dis[1]=1;
q.push(1);
while(!q.empty())
{
int t=q.front();
q.pop();
for(int i=1;i<=m;i++)
{
if(map[t][i]&&!dis[i])
{
q.push(i);
dis[i]=dis[t]+1;
if(i==m)
return 1;
}
}
}
return 0;
}
int dfs(int v,int cap)
{
if(v==m) return cap;
int tp=cap;
for(int i=1;i<=m&&tp;i++)
{
if(map[v][i]&&dis[i]==dis[v]+1)
{
int t=dfs(i,min(tp,map[v][i]));
map[v][i]-=t;
map[i][v]+=t;
tp-=t;
}
}
return cap-tp;
}
void dinic()
{
int flow=0;
while(bfs())
{
flow+=dfs(1,inf);
}
printf("%d\n",flow);
}
int main()
{
int a,b,c;
//freopen("t.txt","r",stdin);
while(scanf("%d%d",&n,&m)!=EOF)
{
memset(map,0,sizeof(map));
while(n--)
{
scanf("%d%d%d",&a,&b,&c);
map[a][b]+=c;
}
dinic();
}
return 0;
}