title: “子树计数模板”
date: 2024-06-03 10:42:02
updated: 2024-06-03 10:42:02
tag: [“notion”, “Algorithm”, “树与图”]
categories: “Algorithm”
mathjax: true
comments: true
description: ‘

• 子树计数模板

子树计数模板

function<int(int,int)> dfs = [&](int x, int fa) { // 当前节点x, x的父节点fa
    int rt = nums[x];//当前节点值nums[x]
    for (int i:g[x]) {
        if (i == fa) continue;
        rt += dfs(i, x);
    }
    return rt;
};