HDU Connections between cities

#include <utility>
#include <algorithm>
#include <string>
#include <cstring>
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <set>
#include <vector>
#include <cmath>
#include <queue>
#include <bitset>
#include <map>
#include <iterator>
using namespace std;
#define clr(a,v) memset(a,v,sizeof(a))
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
const int INF = 0x7f7f7f7f;
const int maxn = 11111;
const int POW = 14;
const double eps = 1e-8;
const int mod = 777777777;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> pii;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
struct node {
	int v, next, w;
	node() {
	}
	node(int v, int next, int w) :
			v(v), next(next), w(w) {
	}
} edge[maxn << 3];
struct Query {
	int v, next, id;
	Query() {
	}
	Query(int v, int next, int id) :
			v(v), next(next), id(id) {
	}
} EDGE[2111111];
int Head[maxn << 1], head[maxn << 1], E, e;
void add_Query(int u, int v, int id) {
	EDGE[E] = Query(v, Head[u], id);
	Head[u] = E++;
}
void add_edge(int u, int v, int w) {
	edge[e] = node(v, head[u], w);
	head[u] = e++;
	edge[e] = node(u, head[v], w);
	head[v] = e++;
}
int dis[maxn];
int f[maxn], p[maxn];
bool vis[maxn];
int ans[2111111];
int find(int n, int f[]) {
	return f[n] == n ? n : f[n] = find(f[n], f);
}
bool connect(int a, int b) {
	int x = find(a, p);
	int y = find(b, p);
	return x == y;
}
void dfs(int u) {
	vis[u] = true;
	int i, v, id, lca;
	for (i = Head[u]; ~i; i = EDGE[i].next) {
		v = EDGE[i].v;
		id = EDGE[i].id;
		if (!connect(u, v)) {
			ans[id >> 1] = -1;
			continue;
		}
		if (vis[v]) {
			lca = find(v, f);
			ans[id >> 1] = dis[u] + dis[v] - dis[lca] * 2;
		}
	}
	for (i = head[u]; ~i; i = edge[i].next) {
		v = edge[i].v;
		if (vis[v])
			continue;
		dis[v] = dis[u] + edge[i].w;
		dfs(v);
		f[v] = u;
	}
}
int main() {
	ios::sync_with_stdio(false);
	int n, m, i, c, u, v, w;
	while (~scanf("%d%d%d", &n, &m, &c)) {
		E = e = 0;
		memset(head, -1, sizeof(head));
		memset(Head, -1, sizeof(Head));
		memset(vis, false, sizeof(vis));
		for (i = 1; i <= n; ++i)
			f[i] = p[i] = i;
		for (i = 0; i < m; ++i) {
			scanf("%d%d%d", &u, &v, &w);
			add_edge(u, v, w);
			u = find(u, p);
			v = find(v, p);
			p[u] = v;
		}
		for (i = 0; i < c; ++i) {
			scanf("%d%d", &u, &v);
			add_Query(u, v, i << 1);
			add_Query(v, u, i << 1 | 1);
		}
		for (i = 1; i <= n; ++i)
			if (!vis[i]) {
				dis[i] = 0;
				dfs(i);
			}
		for (i = 0; i < c; ++i) {
			if (~ans[i])
				printf("%d\n", ans[i]);
			else
				printf("Not connected\n");
		}
	}
	return 0l;
}