Yaroslav has an array that consists of n integers. In one second Yaroslav can swap two neighboring array elements. Now Yaroslav is wondering if he can obtain an array where any two neighboring elements would be distinct in a finite time. Help Yarosla…

题意:初始有一个序列[1,2,...N],一次操作可以将任意两个位置的值互换,Petr做3*n次操作:Alxe做7*n+1次操作.给出最后生成的新序列,问是由谁操作得到的. 分析:一个序列的状态可以归为:由原序列操作奇数次得到(简称奇序列):和操作偶数次(偶序列)得到.显然奇序列中,逆序对的个数为奇数:偶序列中,逆序对的个数为偶.当n为奇数时,3*n为奇,7*n+1为偶:n为偶数时正好相反. 用树状数组或归并排序求逆序对即可. #include<iostream> #include<st…

Police Recruits Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description The police department of your city has just started its journey. Initially, they don’t have any manpower. So, they started hiring n…

E. Alphabet Permutations time limit per test:  1 second memory limit per test:  512 megabytes input:  standard input output: standard output You are given a string s of length n, consisting of first k lowercase English letters. We define a c-repeat o…

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…

http://codeforces.com/problemset/problem/463/D 题意:给出k个排列,问这k个排列的最长公共子序列的长度. 思路:只考虑其中一个的dp:f[i]=max(f[j]+1),其中i这个位置的元素在其他排列里面的位置比j这个位置的元素在其他排列里面位置要靠前. #include<cstdio> #include<cmath> #include<algorithm> #include<cstring> #include&l…

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…

codeforces 895B XK Segments 题目大意: 寻找符合要求的\((i,j)\)对,有:\[a_i \le a_j \] 同时存在\(k\),且\(k\)能够被\(x\)整除,\(k\)满足:\[a_i \le k \le a_j\] 思路: 整体数组排序,对于当前\(a_i\)寻找符合条件的\(a_j\)的最大值和最小值 有:\[(a_i-1)/x+k=a_j/x\] 所以可以通过二分查找获得,这里我寻找\(((a_i-1)/x+k)*x\)为下界,\(((a_i-1)/x…

codeforces 893D Credit Card 题目大意: 有一张信用卡可以使用,每天白天都可以去给卡充钱.到了晚上,进入银行对卡的操作时间,操作有三种: 1.\(a_i>0\) 银行会给卡充入\(a_i\)元 2.\(a_i<0\) 银行从卡中扣除\(a_i\)元 3.\(a_i=0\) 银行对你的卡进行评估,违背了规则就无权再使用此卡 规则1:卡内的余额不得超过\(d\)元 规则2:当\(a_i=0\)时,卡内的余额不能是负数 现在问为了维持信用的平衡,最少去银行几次.(去一次,充…

C. Nice Garland time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You have a garland consisting of nn lamps. Each lamp is colored red, green or blue. The color of the ii-th lamp is sisi ('R',…