题意:一棵树,问每条路径上只出现一次的值的个数的和. 思路: 显然想到考虑边贡献.每条边权下放到下面的哪个点.\(up_i\)为上面第一个点权等于它的点.我们需要一个子树内点权等于它的点(如果满足祖孙关系,不要孙)(除它自己的)sz和. 这样每个点的\(sz\)向\(up\)贡献. 这样差分求出上面的点和下面的点方案数.乘一下就好了 code: 点击查看代码 #include<bits/stdc++.h> using namespace std; const int N=1e6+5; type…

一.原因:  sql语句里边使用 'Y' 'N'  给boolean类型的赋值产生sql失败    二.解决方法:将insert语句中‘Y’或‘N’ 改成TRUE或FALSE即可,共两张表3个地方    本人是改成TRUE或FALSE之后不行,改成了0(假)或1(真)才成功的 (1)INSERT INTO R_VERSION(ID_VERSION, MAJOR_VERSION, MINOR_VERSION, UPGRADE_DATE, IS_UPGRADE) VALUES  (1,5,0,'20…

题目如下: Given an array of integers arr, write a function that returns true if and only if the number of occurrences of each value in the array is unique. Example 1: Input: arr = [1,2,2,1,1,3] Output: true Explanation: The value 1 has 3 occurrences, 2 h…

这是小川的第次更新,第篇原创 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第269题(顺位题号是1207).给定一个整数数组arr,当且仅当该数组中每个元素的出现次数唯一时,返回true. 例如: 输入:arr = [1,2,2,1,1,3] 输出:true 说明:值1出现3次,值2出现2次,值3出现1次.没有两个值出现的次数相同. 输入:arr = [1,2] 输出:false 输入:arr = [-3,0,1,-3,1,1,1,-3,10,0] 输出:true 限制条件:…

Is there a method in Ruby that takes an array, and counts all unique elements and their occurrences and passes them back as a hash? For example ['A','A','A','A','B','B','C'].method > {'A' => 4, 'B' => 2, 'C' => 1} Something like that. ['A','A'…

Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd....". Now we have another string p. Your job is to find…

A string such as "word" contains the following abbreviations: ["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "…

Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n. Example: Given n = 2, return 91. (The answer should be the total numbers in the range of 0 ≤ x < 100, excluding [11,22,33,44,55,66,77,88,99]) Hint: A direct…

An abbreviation of a word follows the form <first letter><number><last letter>. Below are some examples of word abbreviations: a) it --> it (no abbreviation) 1 b) d|o|g --> d1g 1 1 1 1---5----0----5--8 c) i|nternationalizatio|n --&…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 这道题实际上是Catalan Number卡塔兰数的一个例子,如果对卡塔兰数不熟悉的童鞋可能真…