题意:给你两个数x 和 y, x = a + b, y = a XOR b,问有没有合法的a和b满足这个等式? 思路:有恒等式: a + b = ((a & b) << 1) + (a ^ b),所以x - y = ((a & b) << 1), 如果x - y奇数,那就没有合法方案,否则我们可以构造出来.相当于已知a ^ b和a & b, 可以构造一组解了. 代码: #include <bits/stdc++.h> #define ull un…

求[1,n]内k的值的异或和使其值最大 k=1是肯定是n k>1,设pos是n的最高位,那答案就是(1ll<<(pos+1))-1 这里用到一个性质是当S=2^i-1时,a xor (S-a) = S, (a<S) /*此处应有代码*/…

You are given n strings s1, s2, ..., sn consisting of characters 0 and 1. m operations are performed, on each of them you concatenate two existing strings into a new one. On the i-th operation the concatenation saisbi is saved into a new string sn + …

题目传送门 /* 题意:给出无向无环图,每一个点的度数和相邻点的异或和(a^b^c^....) 图论/位运算:其实这题很简单.类似拓扑排序,先把度数为1的先入对,每一次少一个度数 关键在于更新异或和,精髓:a ^ b = c -> a ^ c = b, b ^ c = a; */ #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <…

& -- 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…

题目链接: Problem - B - Codeforces 题目 Example input 4 3 1 1 1 5 1 2 3 4 5 5 0 2 0 3 0 4 1 3 5 1 output 6 0 36 4 题意 给一串数,用这n个数排几种序列,使得 i=1~(n-1) 输出有几种序列满足情况 题解 附  : & -- 位运算之一,有0则0 不用怀疑,一堆数&完后,得到的数<=这堆数的任意一个数 因为每一位只要有一个数==0,这一位就=0,否则为1 记最后&完所有数的…

C. XOR and OR time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The Bitlandians are quite weird people. They do everything differently. They have a different alphabet so they have a differen…

A. Raising Bacteria time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are a lover of bacteria. You want to raise some bacteria in a box. Initially, the box is empty. Each morning, you can…

C. Short Program time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Petya learned a new programming language CALPAS. A program in this language always takes one non-negative integer and retur…

题目链接 New Year Tree 考虑到$ck <= 60$,那么用位运算统计颜色种数 对于每个点,重新标号并算出他对应的进和出的时间,然后区间更新+查询. 用线段树来维护. #include <bits/stdc++.h> using namespace std; #define rep(i, a, b) for (int i(a); i <= (b); ++i) struct node{ long long num, lazy; } tree[ << ]; st…