算法模板模板(逐渐补充)

 并查集

#define N 105
int pre[N];
int rank[N];

int init(int n) {
	for (int i = 0; i < n; i++) {
		pre[i] = i;
		rank[i] = i;
	}
}

int find_pre(int x) {
	if (pre[x] == x) {
		return x;
	}
	return find_pre(pre[x]);
}

int find_pre(int x) {
	if (pre[x] == x) {
		return x;
	}
	return pre[x] = find_pre(pre[x]);
}

bool is_same(int x, int y) {
	int rootx, rooty;
	rootx = find_pre(x);
	rooty = find_pre(y);
	if (rootx == rooty) {
		return ;
	}
	if (rank[rootx] > rank[rooty]) {
		pre[rooty] == rootx; // 大的当根
	}
	else {
		if (rank[rootx] == rank[rooty]) {
			rank[rooty]++;
		}
		pre[rootx] = rooty;
	}
}