competitive-programming/solved-uva/10009.cpp at master · the-redback/competitive-programming · GitHub

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/**
 *                                   ____
 *       ____ ___  ____ ________  __/ __/
 *      / __ `__ \/ __ `/ ___/ / / / /_
 *     / / / / / / /_/ / /  / /_/ / __/
 *    /_/ /_/ /_/\__,_/_/   \__,_/_/
 *
 *    @link : https://the-redback.com
 */
#include <bits/stdc++.h>
using namespace std;

#define inf       HUGE_VAL
#define mem(a, b) memset(a, b, sizeof(a))
#define NN        50
string s;
string ss;
vector<int> edge[NN + 7];
map<string, int> mp;
int dist[NN + 7];
queue<int> q;
vector<string> city;
char a[1050];
char c[1050];

void bfs(int src, int dest) {
    q = queue<int>();
    q.push(src);
    mem(dist, -1);
    dist[src] = 0;
    while (!q.empty()) {
        int k = q.front();
        q.pop();
        for (int i = 0; i < edge[k].size(); i++) {
            if (dist[edge[k][i]] == -1) {
                q.push(edge[k][i]);
                dist[edge[k][i]] = k;
                if (edge[k][i] == dest) return;
            }
        }
    }
    return;
}

void go(int n) {
    if (n < 1) return;
    go(dist[n]);
    printf("%c", city[n][0]);
    return;
}

int main() {
    // freopen("C:\\Users\\Maruf Tuhin\\Desktop\\in.txt","r",stdin);
    int i, j, k, l, n, r;
    int tc, t = 1;
    scanf("%d", &tc);
    while (tc--) {
        scanf("%d%d", &n, &r);
        j = 1;
        city.push_back("0");
        for (i = 0; i < n; i++) {
            scanf("%s%s", &a, &c);
            s.assign(a);
            ss.assign(c);
            if (mp.find(s) == mp.end()) {
                mp[s] = j++;
                city.push_back(s);
            }
            if (mp.find(ss) == mp.end()) {
                mp[ss] = j++;
                city.push_back(ss);
            }
            edge[mp[s]].push_back(mp[ss]);
            edge[mp[ss]].push_back(mp[s]);
        }
        if (t != 1) puts("");
        while (r--) {
            scanf("%s%s", &a, &c);
            s.assign(a);
            ss.assign(c);
            bfs(mp[s], mp[ss]);
            go(dist[mp[ss]]);
            printf("%c\n", city[mp[ss]][0]);
        }
        for (i = 0; i < NN; i++) edge[i].clear();
        mp.clear();
        city.clear();
        t++;
    }
    return 0;
}