Least Common Ancestors 分类： ACM TYPE 2014-10-19 11:24 84人阅读 评论(0) 收藏

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
using namespace std;
struct node
{
int f, s;
};
vector<node>imap[40005];
int deep[40005];
int dis[40005];
int fa[40005];
int ffa[40005];
bool vis[40005];
void dfs(int n,int s,int ff)
{
vis
= true;
for(int i=0;i<imap
.size();i++)
{
if(vis[imap
[i].f])		continue;
deep[imap
[i].f] = s;
dis[imap
[i].f] = dis
+imap
[i].s;
fa[imap
[i].f] = n;
ffa[imap
[i].f] = ff;
dfs(imap
[i].f,s+1,ff);
}
}

int lca(int x, int y)
{
if(x==y)	return dis[x];
if(deep[x]>=deep[y])	return lca(fa[x],y);
else return lca(x,fa[y]);
}
int main()
{
int t, n, m, c;
int u, v, s, ans;
node cur;
while(scanf("%d%d%d",&n,&m,&c)!=EOF)
{
memset(vis,false,sizeof(vis));
memset(fa,0,sizeof(fa));
memset(fa,false,sizeof(fa));
memset(dis,0,sizeof(dis));
memset(deep,false,sizeof(deep));
memset(imap,0,sizeof(imap));
for(int i=0;i<m;i++)
{
scanf("%d%d%d",&u,&v,&s);
cur.f = v;
cur.s = s;
imap[u].push_back(cur);
cur.f = u;
imap[v].push_back(cur);
}
for(int i=1;i<=n;i++)
{
if(vis[i])	continue;
ffa[i] = i;
dfs(i,1,i);
}
for(int i=0;i<c;i++)
{
scanf("%d%d",&u,&v);
if(ffa[u]!=ffa[v])	printf("Not connected\n");
else
{
ans = lca(u,v);
printf("%d\n",dis[u]+dis[v]-2*ans);
}
}

}
return 0;
}