View Code of Problem 1071

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;

const int MAXN = 40004;
typedef pair<int, int> PAIR;

vector<PAIR> edge[MAXN], query[MAXN];
int fa[MAXN], dis[MAXN], ans[MAXN];
bool vis[MAXN];
int n, m;

int father(int x) {
    if (x == fa[x]) return x;
    return fa[x] = father(fa[x]);
}
void Init() {
    scanf("%d %d", &n, &m);
    int a, b, c;
    char d;

    for (int i=0; i<m; i++) {
        scanf("%d %d %d %c", &a, &b, &c, &d);
        edge[a].push_back(PAIR(b, c));
        edge[b].push_back(PAIR(a, c));
    }
    scanf("%d", &m);
    for (int i=0; i<m; i++) {
        scanf("%d %d", &a, &b);
        query[a].push_back(PAIR(b, i));
        query[b].push_back(PAIR(a, i));
    }
    memset(vis, false, sizeof(vis));
}
void dfs(int u, int d) {
    fa[u] = u, dis[u] = d;
    vis[u] = true;
    for (size_t i=0; i<edge[u].size(); i++) {
        int v = edge[u][i].first, w = edge[u][i].second;
        if (!vis[v]) {
            dfs(v, d+w);
            fa[v] = u;
        }
    }

    for (size_t i=0; i<query[u].size(); i++) {
        int v = query[u][i].first, w = query[u][i].second;
        if (vis[v])
            ans[w] = dis[u] + dis[v] - 2*dis[father(v)];
    }

}
int main() {
    Init();
    dfs(1, 0);
    for (int i=0; i<m; i++)
        printf("%d\n", ans[i]);

    return 0;
}