Problem - D1 - Codeforces 题意: 给n个符号(+或-), +代表+1, -代表-1, 求最少删去几个点, 使得     题解(仅此个人理解): 1. 这题打眼一看, 肯定和奇偶有关系, 奇数为+, 偶数为-, 但是删去点这一操作是动态的, 删去某点后, 后面的点的正负随之颠倒, 即奇数位+变偶数位-, 偶数位-变奇数位+, 恰好可以利用该特质 也就是说可以这样理解: 找到一个位置,删去该点并使得后面的点正负颠倒, 最后满足条件. 2. 对于奇数个数, 必须变成偶数个个数…

我果然还是太菜了,就写了两道题....真是水死了.... A The Miracle and the Sleeper 简化题意:给定\(l,r\),求\(a\)%\(b\)的最大值,其中\(r>=a>=b>=l\). 这里规定了是大的数模小的数,考虑选定一个\(b\),显然\(a\)必须比他大,则b%b=0,(b+1)%b=1,(b+2)%b=2...(2b-1)%b=b-1,之后就又从0开始到b-1,显然若\(2b-1<=r\)的话我们就能取到在模b的意义下的最大值,还有的是我们…

& -- 位运算之一,有0则0 原题链接 Problem - 1514B - Codeforces 题目 Example input 2 2 2 100000 20 output 4 226732710 题意 t个测试样例,在每个样例中 数组有n个数,数字范围[ 0, 2k - 1] 使得数组每个数&后,结果=0,并且这n个数的和要尽量大 输出有多少个这样的数组 解析 数组每个数&后,结果=0  -->每一位至少一个0 数要尽量大  -->只要这一位可以 != 0, 就…

全部题目跳转链接 A - The Miracle and the Sleeper 题意 给定\([l, r]\) 求出在这个区间内的两个数字a和b的取模的最大值 (\(a \ge b\)) 分析 上届确定 因此我们最大的取模的值就是 \(\frac {r}{2} + 1\) 但是这个值能取到的条件是\(\frac {r}{2} + 1 \ge l\) 如果上述条件不满足 很显然答案的区间是\([0, r-l]\) AC_CODE #include <bits/stdc++.h> using n…

还是看大佬的题解吧 CFRound#753(Div.3)A-E(后面的今天明天之内补) - 知乎 (zhihu.com) 传送门  Problem - D - Codeforces 题意 n个数字,n个字符, 数字与字符一一对应, 其中字符R红色代表数字可以上升, B蓝色代表可以下降, 问一顿操作下来能否使n个数含有1~n的所有数 题解 当时真的没想到, 蓝色一定在数组前面, 红色一定在数组后面,( 反正就算有方案使得蓝不在前面, 红不在后面,蓝红也是可以交换的). 排序后, 前面的蓝色数字如果…

http://codeforces.com/contest/426/problem/B 对称标题的意思大概是.应当指出的,当线数为奇数时,答案是线路本身的数 #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define maxn 1005 using namespace std; char a[maxn][maxn]; int ans; void solve…

Adieu l'ami. Koyomi is helping Oshino, an acquaintance of his, to take care of an open space around the abandoned Eikou Cram School building, Oshino's makeshift residence. The space is represented by a rectangular grid of n × m cells, arranged into n…

— This is not playing but duty as allies of justice, Nii-chan! — Not allies but justice itself, Onii-chan! With hands joined, go everywhere at a speed faster than our thoughts! This time, the Fire Sisters — Karen and Tsukihi — is heading for somewher…

Even if the world is full of counterfeits, I still regard it as wonderful. Pile up herbs and incense, and arise again from the flames and ashes of its predecessor — as is known to many, the phoenix does it like this. The phoenix has a rather long lif…

Rock... Paper! After Karen have found the deterministic winning (losing?) strategy for rock-paper-scissors, her brother, Koyomi, comes up with a new game as a substitute. The game works as follows. A positive integer n is decided first. Both Koyomi a…