算法详解
238.银河英雄传说(维护与祖宗结点的距离)
#include <iostream>
using namespace std;
const int N = 30010;
int p[N], d[N], size[N];
int a, b;
int find(int x) {
if (p[x] != x) {
int root = find(p[x]);
d[x] += d[p[x]];
p[x] = root;
}
return p[x];
}
int main() {
int T;
scanf("%d", &T);
for (int i = 0; i < N; i ++) {
p[i] = i;
size[i] = 1;
d[i] = 0;
}
while(T --) {
char op[2];
scanf("%s%d%d", op, &a, &b);
if (op[0] == 'M') {
int pa = find(a), pb = find(b);
d[pa] += size[pb];
size[pb] += size[pa];
p[pa] = pb;
} else {
int pa = find(a), pb = find(b);
if (pa != pb) cout << "-1" << endl;
else {
cout << max(abs(d[a] - d[b]) - 1, 0) << endl;
}
}
}
return 0;
}