一中校运会之百米跑(100m Sprint) 题解

思路分析

按题目要求使用对应数据结构与算法模拟/递推求解，注意数据范围边界与时间复杂度。

参考代码

#include <iostream>
#include <vector>
#include <string>
#include <unordered_map>
#include <numeric>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m;
    if (!(cin >> n >> m)) return 0;
    unordered_map<string, int> idMap;
    idMap.reserve(n * 2);
    for (int i = 1; i <= n; ++i) {
        string s;
        cin >> s;
        idMap[s] = i;
    }
    vector<int> p(n + 1);
    iota(p.begin(), p.end(), 0);
    auto find = [&](int x) {
        while (p[x] != x) x = p[x] = p[p[x]];
        return x;
    };
    for (int i = 0; i < m; ++i) {
        string a, b;
        cin >> a >> b;
        int u = idMap[a], v = idMap[b];
        if (u && v) p[find(u)] = find(v);
    }
    int k;
    cin >> k;
    for (int i = 0; i < k; ++i) {
        string a, b;
        cin >> a >> b;
        int u = idMap[a], v = idMap[b];
        if (u && v && find(u) == find(v)) cout << "Yes.\n";
        else cout << "No.\n";
    }
    return 0;
}