[BaekJoon][2644] 촌수계산

BAEKJOON ONLINE JUDGE

한국정보올림피아드 1999

2644 촌수계산

https://www.acmicpc.net/problem/2644

11분

#include <cstdio>
#include <queue>
#include <vector>
using namespace std;
 
int n, one, two;
vector<int> family[101];
int visit[101];
 
void bfs()
{
    queue<int> que;
    que.push(one);
    visit[one] = 1;
 
    while (!que.empty()) {
        int p = que.front();
        que.pop();
 
        if (p == two) {
            printf("%d\n", visit[p] - 1);
            return;
        }
 
        for (int i = 0; i < family[p].size(); i++) {
            if (visit[family[p][i]] == 0) {
                que.push(family[p][i]);
                visit[family[p][i]] = visit[p] + 1;
            }
        }
    }
 
    printf("-1\n");
}
 
int main()
{
    int m;
    int p, c;
 
    scanf("%d %d %d %d", &n, &one, &two, &m);
 
    for (int i = 0; i < m; i++) {
        scanf("%d %d", &p, &c);
        family[p].push_back(c);
        family[c].push_back(p);
    }
 
    bfs();    
 
    return 0;
}