Submission #1707532

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Source Code Expand

# include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <bitset>
# include <complex>
# include <numeric>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
constexpr long long MOD = 10007;
constexpr int INF = 2000000000;
constexpr int HINF = INF / 2;
constexpr double DINF = 100000000000000000.0;
constexpr long long LINF = 9000000000000000000;
constexpr long long HLINF = 4500000000000000000;
const double PI = acos(-1);

constexpr int MAX_V = 100001;
int V, E;
vector<int> G[MAX_V];
int start, goal;

int dis[MAX_V];

int bfs() {
	queue<int>que;

	for (int i = 0; i < MAX_V; i++)dis[i] = INF;

	que.push(start);
	dis[start] = 0;

	while (que.size()) {
		int p = que.front();
		que.pop();



		for (int i = 0; i < G[p].size(); i++) {
			if (dis[G[p][i]] == INF) {
				que.push(G[p][i]);
				dis[G[p][i]] = dis[p] + 1;
			}
		}
	}
	return dis[goal];
}

int main() {
	cin >> V;
	E = V - 1;
	int a, b;
	for (int i = 0; i < E; i++) {
		cin >> a >> b;
		a--, b--;
		G[a].emplace_back(b);
		G[b].emplace_back(a);
	}
	int q;
	cin >> q;
	for (int i = 0; i < q; i++) {
		cin >> start >> goal;
		start--, goal--;
		cout << bfs() + 1 << endl;
	}
}

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