Kruskal和Prim模板

合集 - 模板(41)

1.并查集模板2023-10-312.求质因数模板2023-10-313.二分图最大匹配模板(匈牙利算法)2023-12-024.欧拉函数模板2023-11-305.ST表模板2023-11-266.快速幂模板2023-10-317.字典树模板2023-12-048.矩阵模板2023-12-059.Dijkstra单源最短路模板2023-12-0910.最近公共祖先模板(LCA)2023-12-1211.拓扑排序模板2023-12-1212.区间素数筛模板2023-12-16

13.Kruskal和Prim模板2023-12-24

14.树状数组模板2023-12-2615.二维坐标离散化模板2024-03-0716.单点修改区间查最值-树状数组模板2024-03-1117.KMP模板2024-03-1118.二叉搜索树模板2024-03-3019.DIjkstra进阶模板 路径记录 按权重(结点数最小等)记录2024-03-3120.判断负环模板2024-04-2821.Exgcd 模板2024-05-0322.压位高精度模板2024-05-0623.线段树模板2024-05-1224.扫描线模板2024-05-1825.莫队模板2024-07-1726.带修莫队模板2024-07-1727.SCC缩点模板2024-07-1828.取模+组合数2024-07-2429.FFT 高精度乘法模板2024-07-2430.字符串自然溢出哈希/单哈希/双哈希模板2024-07-2531.树模板2024-07-2732.dsu on tree 模板2024-07-2833.线段树模板重制2024-08-0334.主席树模板2024-08-0735.大数质因数分解模板2024-08-0836.线段树合并模板2024-08-0937.int128输入输出流2024-08-0938.Meissel_Lehmer模板2024-08-0939.浮点高精度2024-08-1340.自适应辛普森法2024-10-0241.unordered_map随机底数种子2024-10-07

收起

例题:P3366 【模板】最小生成树 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)

Kruskal

#include <bits/stdc++.h>
#define debug(a) cout<<#a<<"="<<a<<'\n';
 
using namespace std;
using i64 = long long;
 
typedef pair<i64, i64> PII;
 
struct UFS {
	int sz;
	vector<int> rank, p;
	void link(int x, int y) {
		if (x == y)
			return;
		if (rank[x] > rank[y])
			p[y] = x;
		else
			p[x] = y;
		if (rank[x] == rank[y])
			rank[y]++;
	}
	void init(int n) {
		sz = n;
		rank.resize(n + 1);
		p.resize(n + 1);
		for (int i = 0; i <= sz; i++) {
			p[i] = i;
			rank[i] = 0;
		}
	}
	int find(int x) {
		return x == p[x] ? x : (p[x] = find(p[x]));
	}
	void unin(int x, int y) {
		link(find(x), find(y));
	}
	void compress() {
		for (int i = 0; i < sz; i++)
			find(i);
	}
};
//种类并查集 merge(y + n, x),merge(x + n, y)
 
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
 
	int n, m;
	cin >> n >> m;
	vector<pair<int, PII>> e;
	for (int i = 0; i < m; i ++) {
		int u, v, w;
		cin >> u >> v >> w;
		e.emplace_back(w, PII(u, v));
	}
 
	sort(e.begin(), e.end());
	UFS ufs;
	ufs.init(n);
	i64 ans = 0;
	for (int i = 0; i < m; i ++) {
		auto [w, uv] = e[i];
		auto [u, v] = uv;
		if (ufs.find(u) != ufs.find(v)) {
			ufs.unin(u, v);
			ans += w;
		}
	}
 
	int op = ufs.find(1);
	for (int i = 1; i <= n; i ++) {
		if (ufs.find(i) != op) {
			cout << "orz" << '\n';
			return 0;
		}
	}
 
	cout << ans << '\n';
 
	return 0;
}

Prim

#include <bits/stdc++.h>
#define debug(a) cout<<#a<<"="<<a<<'\n';
 
using namespace std;
using i64 = long long;
 
typedef pair<i64, i64> PII;
 
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
 
	int n, m;
	cin >> n >> m;
	vector g(n + 1, vector<PII>());
	vector<int> dis(n + 1);
	vector<bool> vis(n + 1);
	i64 ans = 0, cnt = 0;
	for (int i = 0; i < m; i ++) {
		int u, v, w;
		cin >> u >> v >> w;
		g[u].emplace_back(v, w);
		g[v].emplace_back(u, w);
	}
 
	priority_queue<PII, vector<PII>, greater<PII>> Q;
	Q.push({0, 1});
	while (Q.size()) {
		auto [w, u] = Q.top();
		Q.pop();
 
		if (vis[u]) continue;
		vis[u] = true;
		ans += w;
		cnt ++;
		dis[u] = w;
		for (auto [v, d] : g[u]) {
			if (!vis[v]) {
				Q.push({d, v});
			}
		}
	}
 
	if (cnt != n) {
		cout << "orz\n";
	} else
		cout << ans << '\n';
    
	return 0;
}