HDU 5889 Barricade 【BFS+最小割 网络流】(2016 ACM/ICPC Asia Regional Qingdao Online)

//
//by coolxxx
//#include<bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<string>
#include<iomanip>
#include<map>
#include<stack>
#include<queue>
#include<set>
#include<bitset>
#include<memory.h>
#include<time.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
//#include<stdbool.h>
#include<math.h>
#define min(a,b) ((a)<(b)?(a):(b))
#define max(a,b) ((a)>(b)?(a):(b))
#define abs(a) ((a)>0?(a):(-(a)))
#define lowbit(a) (a&(-a))
#define sqr(a) ((a)*(a))
#define swap(a,b) ((a)^=(b),(b)^=(a),(a)^=(b))
#define mem(a,b) memset(a,b,sizeof(a))
#define eps (1e-10)
#define J 10000
#define mod 1000000007
#define MAX 0x7f7f7f7f
#define PI 3.14159265358979323
#pragma comment(linker,"/STACK:1024000000,1024000000")
#define N 1004
#define M 10004
using namespace std;
typedef long long LL;
double anss;
LL aans;
int cas,cass;
int n,m,lll,ans;
int nn,S,T;
int d
,vd
,last
,last1
;
bool u
;
struct xxx
{
int next,to,q;
}a[M<<1],b[M<<1];
void add(int x,int y,int z)
{
a[++lll].next=last[x];
a[lll].to=y;
a[lll].q=z;
last[x]=lll;
}
void link(int x,int y,int z)
{
b[++cas].next=last1[x];
b[cas].to=y;
b[cas].q=z;
last1[x]=cas;
}
int sap(int u,int f)
{
int i,v,tt,asp=0,mix=nn-1;
if(u==T)return f;
for(i=last[u];i;i=a[i].next)
{
v=a[i].to;
if(a[i].q>0)
{
if(d[u]==d[v]+1)
{
tt=sap(v,min(f-asp,a[i].q));
asp+=tt;
a[i].q-=tt;
a[i^1].q+=tt;
if(asp==f || d[S]==nn)
return asp;
}
mix=min(mix,d[v]);
}
}
if(asp!=0)return asp;
if(!--vd[d[u]])d[S]=nn;
else vd[d[u]=mix+1]++;
return asp;
}
void bfs()
{
int now,to,i;
queue<int>q;
mem(d,MAX);
u
=1;q.push(n);d
=0;
while(!q.empty())
{
now=q.front();q.pop();
if(d[now]>=d[S])continue;
for(i=last1[now];i;i=b[i].next)
{
to=b[i].to;
if(d[now]+1>d[to])continue;
d[to]=d[now]+1;
add(now,to,0),add(to,now,b[i].q);
if(!u[to])
{
u[to]=1;
if(to!=S)q.push(to);
}
}
}
mem(d,0);
}
int main()
{
#ifndef ONLINE_JUDGEW
freopen("1.txt","r",stdin);
//    freopen("2.txt","w",stdout);
#endif
int i,j,k;
int x,y,z,f;
//    init();
for(scanf("%d",&cass);cass;cass--)
//    for(scanf("%d",&cas),cass=1;cass<=cas;cass++)
//    while(~scanf("%s",s))
//    while(~scanf("%d",&n))
{
lll=cas=1;ans=0;
mem(u,0);mem(vd,0);mem(last,0);mem(last1,0);
scanf("%d%d",&n,&m);
for(i=1;i<=m;i++)
{
scanf("%d%d%d",&x,&y,&z);
link(x,y,z),link(y,x,z);
}
nn=n;
S=1,T=n;
vd[0]=nn;
bfs();
while(d[S]<nn)
{
f=sap(S,MAX);
ans+=f;
}
printf("%d\n",ans);
}
return 0;
}
/*
//

//
*/