这是DFS系列的第二篇 割边的概念 In graph theory, a bridge, isthmus, cut-edge, or cut arc is an edge of a graph whose deletion increases its number of connected components. Equivalently, an edge is a bridge if and only if it is not contained in any cycle. A graph i
/* 题意:将两端涂有颜色的木棒连在一起,并且连接处的颜色相同! 思路:将每一个单词看成一个节点,建立节点之间的无向图!判断是否是欧拉回路或者是欧拉路 并查集判通 + 奇度节点个数等于2或者0 */ #include<cstring> #include<cstdio> #include<algorithm> #define N 2500005*2 using namespace std; int f[N]; ]; int rank[N]; int deg[N]; int
Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not. You need to merge them into a new binary tree. The merge rule is that if two nodes overlap, then
合并二叉树 给定两个二叉树,想象当你将它们中的一个覆盖到另一个上时,两个二叉树的一些节点便会重叠. 你需要将他们合并为一个新的二叉树.合并的规则是如果两个节点重叠,那么将他们的值相加作为节点合并后的新值,否则不为 NULL 的节点将直接作为新二叉树的节点. 示例 1: 输入: 输出: 合并后的树: 注意: 合并必须从两个树的根节点开始. /** * Definition for a binary tree node. * public class TreeNode { * int val; *