记录编号 |
300581 |
评测结果 |
AAAAAAAAAAAA |
题目名称 |
[USACO Feb05] 神秘的挤奶机 |
最终得分 |
100 |
用户昵称 |
mildark |
是否通过 |
通过 |
代码语言 |
C++ |
运行时间 |
1.138 s |
提交时间 |
2016-08-28 18:50:43 |
内存使用 |
0.32 MiB |
显示代码纯文本
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<vector>
#include<cassert>
using namespace std;
const int INF=0x7fffffff/2;
const int SIZEN=210;
class Edge{
public:
int from,to,cap,flow,cost;
};
vector<Edge> edges;
vector<int> c[SIZEN];
void addedge(int from,int to,int cap,int cost){
edges.push_back((Edge){from,to,cap,0,cost});
edges.push_back((Edge){to,from,cap,0,cost});
int tot=edges.size()-2;
c[from].push_back(tot);
c[to].push_back(tot+1);
}
int N,S,T;
int f[SIZEN],father[SIZEN];
int ansflow=0,anscost=0;
bool Prim_one(int S){
static bool used[SIZEN];
for(int i=0;i<=N;i++) f[i]=INF;
memset(used,0,sizeof(used));
f[S]=0;
while(true){
int x=-1;
for(int i=0;i<=N;i++){
if(used[i]) continue;
if(x==-1||f[i]<f[x]) x=i;
}
if(x==-1) break;
used[x]=true;
for(int i=0;i<c[x].size();i++){
Edge &e=edges[c[x][i]];
if(e.cap<=e.flow) continue;
if(used[e.to]) continue;
int now;
if(e.flow==0) now=max(f[x],e.cost);
else if(e.flow<0) now=f[x];
if(now<f[e.to]){
f[e.to]=now;
father[e.to]=c[x][i];
}
}
}
if(!used[T]) return false;
ansflow++;
anscost=max(anscost,f[T]);
int x=T;
while(x!=S){
int now=father[x];
edges[now].flow++;
edges[now^1].flow--;
x=edges[now].from;
}
return true;
}
int MCMF(int mustflow){
ansflow=anscost=0;
for(int i=1;i<=mustflow;i++){
assert(Prim_one(S));
}
return anscost;
}
int n,m,rides;
void makegraph(void){
scanf("%d%d%d",&n,&m,&rides);
N=n;S=1;T=N;
int a,b,w;
for(int i=1;i<=m;i++){
scanf("%d%d%d",&a,&b,&w);
addedge(a,b,1,w);
}
}
int main(){
freopen("secretmilking.in","r",stdin);
freopen("secretmilking.out","w",stdout);
makegraph();
printf("%d\n",MCMF(rides));
return 0;
}