Number Of Permutations 思路:利用容斥,首先所有可能的排列肯定是fac[n],然后可能会有三种 bad 的情况: ①第一个元素的排列是非递减 ②第二种是第二个元素的排列是非递减 ③这两个可能出现的重叠情况,意思就是说同时导致①②成立 这个时候我们利用容斥的思想,用fac[n]-①-②+③即可 我们把所有的pair按照第一个元素优先排列的方式把所有的pair sort 一下( sort 对pair的排序方式是默认第一个元素优先的),这个时候我们就保证了所有pair的第一个元素…

D. Number Of Permutations time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given a sequence of nn pairs of integers: (a1,b1),(a2,b2),…,(an,bn)(a1,b1),(a2,b2),…,(an,bn). This sequenc…

题意:https://codeforc.es/contest/1207/problem/D n个元素,每个元素有a.b两个属性,问你n个元素的a序列和b序列有多少种排序方法使他们不同时非递减(不同时good). 思路: 真难则反+容斥,反向考虑,ans1=如果a序列非递减则有a中各个数字出现次数的阶乘的乘积个,ans2=b序列也是一样. ans3=然后还要减去a序列和b序列都是good的方案数,就是元素相同的出现次数阶乘的乘积(注意,如果不存在双good就不算ans3). ANS就是:全排列 -…

挺水的一道题~ 拿全排列随便乘一下就好了. #include <cstdio> #include <algorithm> #define N 300004 #define ll long long #define mod 998244353 #define setIO(s) freopen(s".in","r",stdin) using namespace std; struct Node { int a,b; }t[N]; ll fac[N…

题目大意 给你n个二元组 问你有几种排列是的按两个关键字中的任意一个都不是不降排列的 分析 不妨容斥 我们先加上总的方案数$n!$ 之后我们按第一个关键字排序 因为值相同的情况下不影响答案 所以让总方案数减去$\prod sum_{ai}!$即可 对于第二关键字的情况同上 我们再使序列同时按照第一关键字和第二关键字排序 然后总方案数加上$\prod sum_{(ai,bi)}!$即可 代码 #include<iostream> #include<cstdio> #include&l…

C. Iahub and Permutations time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Iahub is so happy about inventing bubble sort graphs that he's staying all day long at the office and writing permu…

Problem Description The signature of a permutation is a string that is computed as follows: for each pair of consecutive elements of the permutation, write down the letter 'I' (increasing) if the second element is greater than the first one, otherwis…

转载请注明出处: http://www.cnblogs.com/fraud/          ——by fraud Iahub and Permutations Iahub is so happy about inventing bubble sort graphs that he's staying all day long at the office and writing permutations. Iahubina is angry that she is no more import…

Number String Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1016    Accepted Submission(s): 440 Problem Description The signature of a permutation is a string that is computed as follows: fo…

Number String Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1027 Accepted Submission(s): 448 Problem Description The signature of a permutation is a string that is computed as follows: for each…