【题解】
弗洛伊德。更新距离的时候把$f[i][j]=min(f[i][j],f[i][k]+f[k][j])$改为$f[i][j]=min(f[i][j],max(f[i][k],f[k][j]))$.
#include<cstdio>
#include<algorithm>
#include<cstring>
#define N (400)
#define rg register
using namespace std;
int n,m,t,a[N][N];
inline int read(){
int k=0,f=1; char c=getchar();
while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar();
while('0'<=c&&c<='9')k=k*10+c-'0',c=getchar();
return k*f;
}
int main(){
n=read(); m=read(); t=read();
for(rg int i=1;i<=n;i++)
for(rg int j=1;j<=n;j++) if(i!=j) a[i][j]=1e9;
for(rg int i=1,u,v;i<=m;i++) u=read(),v=read(),a[u][v]=read();
for(rg int k=1;k<=n;k++)
for(rg int i=1;i<=n;i++)
for(rg int j=1;j<=n;j++)
a[i][j]=min(a[i][j],max(a[i][k],a[k][j]));
for(rg int i=1;i<=t;i++){
int u=read(),v=read();
if(a[u][v]==1e9) puts("-1");
else printf("%d
",a[u][v]);
}
return 0;
}