题目链接:http://codeforces.com/contest/600/problem/C C. Make Palindrome time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A string is called palindrome if it reads the same from left to right an…
C. Make Palindrome Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/600/problem/C Description A string is called palindrome if it reads the same from left to right and from right to left. For example "kazak", "oo&q…
D. Sum in the tree 题目链接:https://codeforces.com/contest/1099/problem/D 题意: 给出一棵树,以及每个点的si,这里的si代表从i号结点到根节点的权值和.但是有些si=-1,这就相当于丢失了当前结点的数据. 假设原本每个点的权值为ai,那么现在求sum{ai}的最小为多少,ai为非负数. 题解: 这题可以单独看每一条链上的s值,假设当前结点为u,儿子结点v,那么就有几种情况: 1.su==-1&&sv==-1,这种不用管,继…
D. Sum in the tree 题意 给出一颗树,奇数层数的点有值,值代表从1到该点的简单路的权值的和,偶数层数的点权值被擦去了 问所有节点的和的最小可能是多少 思路 对于每一个-1(也就是值未知的点)其所填的值的最小值小于等于他的自己点中已知的点的权值 换个说法就是 一个-1点有多个子树 那么这个点的值最小也是这几个子树里面的最大的值,才能使得其合法 从根节点递归求值即可 其中注意 这里计算权值和的时候,因为已知每个点到根节点的路径的点的权值和所以计算一个节点以及其子树到根节点的权值和的…
A. Sum in the tree Mitya has a rooted tree with nn vertices indexed from 11 to nn, where the root has index 11. Each vertex vv initially had an integer number av≥0av≥0 written on it. For every vertex vv Mitya has computed svsv: the sum of all values…
Let's assume that v(n) is the largest prime number, that does not exceed n; u(n) is the smallest prime number strictly greater than n. Find . Input The first line contains integer t (1 ≤ t ≤ 500) — the number of testscases. Each of the following t li…
