分析
floyd,只是方程改一下
dis[i][j]=min(max(dis[i][k],dis[k][j]),dis[i][j])dis[i][j]=min(max(dis[i][k],dis[k][j]),dis[i][j])dis[i][j]=min(max(dis[i][k],dis[k][j]),dis[i][j])
注意是有向图
code
#include<bits/stdc++.h>
using namespace std;
#define loop(i,start,end) for(int i=start;i<=end;++i)
#define clean(arry,num); memset(arry,num,sizeof(arry));
#define max(a,b) ((a>b)?a:b)
#define min(a,b) ((a<b)?a:b)
int n,m,t;
const int maxn=310,maxm=25010;
int dis[maxn][maxn];
int ans[maxn][maxn];
inline int read()
{
int ans=0;bool neg=false;char r=getchar();
while(r>'9'||r<'0'){if(r=='-')neg=true;r=getchar();}
while(r>='0'&&r<='9'){ans=ans*10+r-'0';r=getchar();}
return (neg)?-ans:ans;
}
void floyd()
{
loop(k,1,n)
loop(i,1,n)
loop(j,1,n)dis[i][j]=min(max(dis[i][k],dis[k][j]),dis[i][j]);//dis[i][j]=min(dis[i][k]+dis[k][j],dis[i][j]);
}
int main()
{
#ifndef ONLINE_JUDGE
freopen("datain.txt","r",stdin);
#endif
clean(dis,0x3f);clean(ans,0x3f);
n=read(),m=read(),t=read();
int s,e,w;
loop(i,1,m)s=read(),e=read(),w=read(),dis[s][e]=min(dis[s][e],w)/*,dis[e][s]=dis[s][e],ans[s][e]=ans[e][s]=dis[e][s]*/;
floyd();
loop(i,1,t)
{
int ai,bi;
ai=read(),bi=read();
printf("%d\n",(dis[ai][bi]>1000000)?-1:dis[ai][bi]);
}
return 0;
}