题意: 给出一个具有N个点的树,现在给出两种操作: 1.get x,表示询问以x作为根的子树中,1的个数. 2.pow x,表示将以x作为根的子树全部翻转(0变1,1变0). 思路:dfs序加上一个线段树区间修改查询. AC代码: #include<iostream>#include<vector>#include<string.h>using namespace std;const int maxn=2e5+5;int sum[maxn<<2],lazy[…

E. Little Girl and Problem on Trees time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A little girl loves problems on trees very much. Here's one of them. A tree is an undirected connected g…

A. Alex and broken contest time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problems…

Codeforces Round #622 (Div. 2) A. Fast Food Restaurant 题意: 你是餐馆老板,虽然只会做三道菜,上菜时还有个怪癖:一位客人至少上一道菜,且一种菜最多上一次,所有客人菜单不能相同.给出三种菜的数量,问最多能接收多少客人. 思路: 一人一道 → 一人两道 → 一人三道. #include <bits/stdc++.h> using namespace std; int main() { int t;cin>>t; while(t--…

http://codeforces.com/contest/877/problem/E 真的菜的不行,自己敲一个模板,到处都是问题.哎 #include <bits/stdc++.h> using namespace std; ; #define lson (q<<1) #define rson ((q<<1)|1) struct node { int l,r,mid; int v,lazy; }tree[maxn*]; int L[maxn],R[maxn],inde…

A. Alex and broken contest 题意 判断一个字符串内出现五个给定的子串多少次. Code #include <bits/stdc++.h> char s[110]; using namespace std; typedef long long LL; char* rec[5] = {"Danil", "Olya", "Slava", "Ann", "Nikita"}; i…

E. Danil and a Part-time Job 题目链接:http://codeforces.com/contest/877/problem/E time limit per test2 seconds memory limit per test256 megabytes Danil decided to earn some money, so he had found a part-time job. The interview have went well, so now he i…

A. Alex and broken contest time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problems…

[链接] 我是链接,点我呀:) [题意] 在这里输入题意 [题解] 注意是所有的名字里面,只出现了其中某一个名字一次. [代码] #include <bits/stdc++.h> using namespace std; const string temp[] = {"Danil","Olya","Slava","Ann","Nikita"}; string s; int num[5]; int…

[链接] 我是链接,点我呀:) [题意] 给一张二维点格图,其中有一些点可以走,一些不可以走,你每次可以走1..k步,问你起点到终点的最短路. [题解] 不能之前访问过那个点就不访问了.->即k那一层循环直接break; 因为可能出现这种 ax aa aa 然后起点是(3,2)终点是(1,1);然后k=3 bfs的时候,第一步,走到了(2,2)和(3,1); 但是接下来,如果(2,2)先走的话,就会先走到(2,1); 而(3,1)认为(2,2)走过了,就不往下走了. ->但实际上他可以一步走到…

[链接] 我是链接,点我呀:) [题意] 有n个位置,每个位置都可能有不定数量的tank; 你每次可以选择一个位置投掷炸弹. 并且,这个位置上的所有tank都会受到你的攻击. 并且失去一点体力. 然后它们可能会往左走一格,或者往右走一格. 每个tank的体力都为2. 问你打掉所有的tank最坏情况要多少次轰炸操作.然后输出所有的轰炸位置. [题解] 在2,4,6...轰炸 然后在1,3,5...轰炸 最后在2,4,6轰炸. 可以保证每个tank都被炸死. [代码] #include <bits/…

[链接] 我是链接,点我呀:) [题意] 在这里输入题意 [题解] 枚举中间那一段从哪里开始.哪里结束就好 注意为空的话,就全是a. 用前缀和优化一下. [代码] #include <bits/stdc++.h> using namespace std; const int N = 5e3; string s; int a[N+10],pre[N+10][2],ans; int main(){ //freopen("rush.txt","r",stdin…

B. Nikita and string One day Nikita found the string containing letters "a" and "b" only. Nikita thinks that string is beautiful if it can be cut into 3 strings (possibly empty) without changing the order of the letters, where the 1-st…

题意:求最长可以分a b a为三部分子串,a b a可以为空 思路在代码里 1 #include<cstdio> 2 #include<iostream> 3 #include<cstring> 4 #include<cmath> 5 #include<algorithm> 6 #define maxn 505 7 using namespace std; 8 int main(){ 9 char a[5001]; 10 int b[5001],…

A. Mike and palindrome time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the s…

题目链接:http://codeforces.com/contest/979/problem/C 大致题意 给出n个点,有n-1个边将他们链接.给出x,y,当某一路径中出现x....y时,此路不通.路径(u,v)和(v,u)是不同的. 思路:一开始大神是给每个点都用BFS找出能到的点的路径,同时记录搜索的状态,但出了点小问题,估计修正了也回超时,现在给出大神思路,因为不能自己到自己所以点对数肯定是n*(n-1)这是全部的可能,那我们只要找出不可能的情况相减,那就是答案的对不对?这是肯定的,现在我…

A. One-dimensional Japanese Crossword time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Recently Adaltik discovered japanese crosswords. Japanese crossword is a picture, represented as a tabl…

A. Find Extra One time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You have n distinct points on a plane, none of them lie on OY axis. Check that there is a point after removal of which the…

C. White Sheet There is a white sheet of paper lying on a rectangle table. The sheet is a rectangle with its sides parallel to the sides of the table. If you will take a look from above and assume that the bottom left corner of the table has coordina…

A. Appleman and Easy Task time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Toastman came up with a very easy task. He gives it to Appleman, but Appleman doesn't know how to solve it. Can you…

A. Magic Numbers time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A magic number is a number formed by concatenation of numbers 1, 14 and 144. We can use each of these numbers any number of…

You are given nn integer numbers a1,a2,…,ana1,a2,…,an. Consider graph on nn nodes, in which nodes ii, jj (i≠ji≠j) are connected if and only if, aiaiAND aj≠0aj≠0, where AND denotes the bitwise AND operation. Find the length of the shortest cycle in th…

题意:给你一个长度为\(n\)的序列\(a\).对它重新排列,使得\(a_{i+1}=a_{i}/3\)或\(a_{i+1}=2*a_{i}\).输出重新排列后的序列. 题解:经典DFS,遍历这个序列,对每个数dfs,每次dfs使\(len+1\),当\(len=n\)时,说明这个序列已经满足条件了,输出并且标记一下,防止还有另外的情况导致多输出. 代码: #include <iostream> #include <cstdio> #include <cstring>…

Codeforces Round #177 (Div. 1) A. Polo the Penguin and Strings 题意 让你构造一个长度为n的串,且里面恰好包含k个不同字符,让你构造的字符串字典序最小. 题解 先abababab,然后再把k个不同字符输出,那么这样就是最少 代码 #include<bits/stdc++.h> using namespace std; string s; int main() { int n,k; scanf("%d%d",&am…

Codeforces Round #738 (Div. 2) 跳转链接 A. Mocha and Math 题目大意 有一个长度为\(n\)的数组 可以进行无数次下面的操作,问操作后数组中的最大值的最小值是多少 - 操作为:选两个位置\([l,r]\) 如果数组中从\(l\)到\(r\)中每个元素\(a_{l+i}\)变为 \(a_{l+i}\)&\(a_{r-i}\) 思路 &操作是对于每一位上的数字,如果有一个\(0\)则当前位置上就为\(0\) 因此我们可以知道 当某个数字某位变成\…

目录 Codeforces 1000 A.Codehorses T-shirts B.Light It Up C.Covered Points Count(差分) D.Yet Another Problem On a Subsequence(DP) E.We Need More Bosses(圆方树) \(Description\) \(Solution\) F.One Occurrence(线段树) \(Description\) \(Solution\) G.Two-Paths(树形DP)…

题目链接   Danil and a Part-time Job 题意    给出一系列询问或者修改操作 $pow$ $x$表示把以$x$为根的子树的所有结点的状态取反($0$变$1$,$1$变$0$) $get$  $x$表示求以$x$为根的子树中状态为$1$的结点数. 首先大力$dfs$序,然后线段树操作一下. 具体问题转化为:区间翻转,区间求和. #include <bits/stdc++.h> using namespace std; #define rep(i, a, b) for…

Codeforces Round #366 (Div. 2) A I hate that I love that I hate it水题 #I hate that I love that I hate it n = int(raw_input()) s = "" a = ["I hate that ","I love that ", "I hate it","I love it"] for i in ran…

Codeforces Round #354 (Div. 2) Problems     # Name     A Nicholas and Permutation standard input/output 1 s, 256 MB    x3384 B Pyramid of Glasses standard input/output 1 s, 256 MB    x1462 C Vasya and String standard input/output 1 s, 256 MB    x1393…

直达–>Codeforces Round #368 (Div. 2) A Brain’s Photos 给你一个NxM的矩阵,一个字母代表一种颜色,如果有”C”,”M”,”Y”三种中任意一种就输出”#Color”,如果只有”G”,”B”,”W”就输出”#Black&White”. #include <cstdio> #include <cstring> using namespace std; const int maxn = 200; const int INF =…