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为什么RE了,求高人指点我用的是二分查找+ISAP求最大流,感觉不会RE啊
#include<iostream>
#include<queue>
#include<algorithm>
using namespace std;
const int VMAX=233;
int K,C,M,V;
int p[3501],l=0;
int a[VMAX][VMAX],c[VMAX][VMAX],d[VMAX],pre[VMAX],sumd[VMAX];
void set()
{
int t=V-1;
memset(d,1,sizeof(d));
memset(sumd,0,sizeof(sumd));
queue<int> P;
P.push(t);
d[t]=0;
sumd[0]=1;
while(!P.empty())
{
int k=P.front(); P.pop();
for(int i=0;i<V;i++)
if(c[i][k]&&d[i]>=V)
{
P.push(i);
d[i]=d[k]+1;
sumd[d[i]]++;
}
}
}
int find(int i)
{
for(int j=0;j<V;j++)
if(c[i][j]&&d[i]==d[j]+1)
return j;
return -1;
}
int num(int i)
{
int t=1000000000;
for(int j=0;j<V;j++)
if(c[i][j]&&d[j]+1<t)
t=d[j]+1;
return (t==1000000000)?V:t;
}
int maxflow(int s,int t)//ISAP
{
set();
int i=s,sumflow=0;
while(d[s]<V)
{
int k=find(i);
if(k>=0)
{
pre[k]=i;
i=k;
if(i==t)
{
int flow=1000000000;
for(i=t;i!=s;i=pre[i])
if(flow>c[pre[i]][i])
flow=c[pre[i]][i];
for(i=t;i!=s;i=pre[i])
{
c[pre[i]][i]-=flow;
c[i][pre[i]]+=flow;
}
sumflow+=flow;
}
}
else
{
int x=num(i);
if(--sumd[d[i]]==0) break;
d[i]=x;
sumd[x]++;
if(i!=s) i=pre[i];
}
}
return sumflow;
}
int check(int x)//构图
{
memset(c,0,sizeof(c));
for(int i=0;i<K;i++)
for(int j=K;j<K+C;j++)
if(a[i][j]<=x)
c[i][j]=1;
for(int i=0;i<K;i++)
c[V-2][i]=M;
for(int i=K;i<K+C;i++)
c[i][V-1]=1;
int o=maxflow(V-2,V-1);
if(o>=C) return 1;
else return 0;
}
int main()
{
cin>>K>>C>>M;
V=K+C;
for(int i=0;i<V;i++)
for(int j=0;j<V;j++)
{
cin>>a[i][j];
if(a[i][j]==0) a[i][j]=1000000000;
}
for(int k=0;k<V;k++)//Floyd
for(int i=0;i<V;i++)
for(int j=0;j<V;j++)
if(a[i][k]+a[k][j]<a[i][j])
a[i][j]=a[i][k]+a[k][j];
V+=2;
int low,high;
for(int i=0;i<K;i++)
for(int j=K;j<K+C;j++)
{
if(a[i][j]>high&&a[i][j]!=1000000000) high=a[i][j];
if(a[i][j]<low) low=a[i][j];
}
while(low<=high)//二分查找
{
int mid=(low+high)/2;
if(check(mid)==1) high=mid-1;
else low=mid+1;
}
cout<<low<<endl;
return 0;
}
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