백준 15591번 MooTube (Silver) C++

https://www.acmicpc.net/problem/15591

15591번: MooTube (Silver)

 

bfs

 

#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;

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

int n, q;

void RefreshFound() { for (auto a : found) a = false; }

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    
    cin >> n >> q;
    graph = vector<vector<pair<int, int>>>(n + 1, vector<pair<int, int>>());
    found = vector<bool>(n + 1, false);
    for (int i = 0; i < n - 1; i++) {
        int p, q, r;
        cin >> p >> q >> r;
        graph[p].push_back({ q,r });
        graph[q].push_back({ p,r });
    }
    for (int i = 0; i < q; i++) {
        int k, v;
        cin >> k >> v;
        int cnt = 0;
        queue<pair<int, int>> q;
        q.push({ v,1000000001 });
        found[v] = true;
        while (!q.empty()) {
            auto curr = q.front();
            q.pop();
            if (curr.second >= k && curr.first != v) cnt++;
            for (auto next : graph[curr.first]) {
                if (found[next.first]) continue;
                found[next.first] = true;
                q.push({ next.first,min(curr.second,next.second) });
            }
        }
        RefreshFound();
        cout << cnt << "\n";
    }
}