백준 1240번 노드사이의 거리 C++

https://www.acmicpc.net/problem/1240

1240번: 노드사이의 거리

 

dfs

 

#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <utility>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <limits.h>

using namespace std;
using int64 = long long; 

int n, m;
int ans;

vector<vector<pair<int, int>>> graph;
vector<bool> visited;

void dfs(int curr, int target, int dist) {
    if (curr == target) {
        ans = dist;
        return;
    }
    visited[curr] = true;
    for (auto next : graph[curr]) {
        if (visited[next.first]) continue;
        dfs(next.first, target, dist + next.second);
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n >> m;
    graph = vector<vector<pair<int, int>>>(n + 1, vector<pair<int, int>>());
    visited = vector<bool>(n + 1, false);
    for (int i = 0; i < n - 1; i++) {
        int s, e, d;
        cin >> s >> e >> d;
        graph[s].push_back({ e,d });
        graph[e].push_back({ s,d });
    }
    for (int i = 0; i < m; i++) {
        for (auto a : visited) a = false;
        int s, e;
        cin >> s >> e;
        dfs(s, e, 0);
        cout << ans << "\n";
    }
}