poj 1273 Drainage Ditches

http://poj.org/problem?id=1273
#include<iostream>

#include<cmath>

#include<string>

#include<algorithm>

#include<queue>

#include<cstring>

#include<cstdio>



using namespace std;

const int MAX=2000000005;

const int N=205;

int h[N];

int flow[N][N];



int Bfs(int n)

{

    memset(h,0,sizeof(h));

    queue<int>str;

    str.push(1);

    h[1]=1;

    while(!str.empty())

    {

        int k=str.front();

        str.pop();

        for(int i=1;i<=n;++i)

        {

            if(h[i]==0&&flow[k][i]>0)

            {

                h[i]=h[k]+1;

                str.push(i);

            }

        }

    }

    return h[n];

}

int end;

int Add(int x,int M)

{

    if(x==end)

    return M;

    int sum=M;

    for(int i=1;i<=end;++i)

    {

        if(flow[x][i]>0&&h[i]==h[x]+1)

        {

            int w=Add(i,min(sum,flow[x][i]));

            sum=sum-w;

            flow[x][i]-=w;

            flow[i][x]+=w;

            if(sum==0)

            break;

        }

    }

    return (M-sum);

}

int main()

{

    int n,m;

    while(cin>>n>>m)

    {

        end=m;

        memset(flow,0,sizeof(flow));

        while(n--)

        {

            int i,j,k;

            cin>>i>>j>>k;

            flow[i][j]+=k;

        }

        int ans=0;

        while(Bfs(m))

        {

           ans+=Add(1,MAX);

        }

        cout<<ans<<endl;

    }

    return 0;

}