题目大意:有n个数排成一列,问从中能找出几个三元组(ai,aj,ak)满足i<j<k并且这三个数严格单调. 题目分析:枚举中间的数字aj,如果aj前面有c(j)个数a(j)小,后面有d(j)个数比a(j)小,那么aj为中间数时,共有c(j)*(n-j-d(j))+d(j)*(j-1-c(j)).定义x(i)表示 i 出现过几次,当枚举到aj 时,只需统计sum(x(1)~x(a(j)-1)便得c(j),d(j)求法类似. 代码如下: # include<iostream> # in
B. Powers of Two You are given n integers a1, a2, ..., an. Find the number of pairs of indexes i, j (i < j) that ai + aj is a power of 2 (i. e. some integer xexists so that ai + aj = 2x). Input The first line contains the single positive integer n
xiaoxin and his watermelon candy 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5654 Description During his six grade summer vacation, xiaoxin got lots of watermelon candies from his leader when he did his internship at Tencent. Each watermelon cand
A. Ultra-Fast Mathematician time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Shapur was an extremely gifted student. He was great at everything including Combinatorics, Algebra, Number Theo
1. 1-bit and 2-bit Characters We have two special characters. The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11). Now given a string represented by several bits. Return whether the last
pid=5654">[HDOJ 5654] xiaoxin and his watermelon candy(离线+树状数组) xiaoxin and his watermelon candy Time Limit: 4000/4000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 233 Accepted Submission(s): 61 Problem Des
Given a sequence of n integers a1, a2, ..., an, a 132 pattern is a subsequence ai, aj, ak such that i < j < k and ai < ak < aj. Design an algorithm that takes a list of n numbers as input and checks whether there is a 132 pattern in the list.
463. Island Perimeterhttps://leetcode.com/problems/island-perimeter/就是逐一遍历所有的cell,用分离的cell总的的边数减去重叠的边的数目即可.在查找重叠的边的数目的时候有一点小技巧,就是沿着其中两个方向就好,这种题目都有类似的规律,就是可以沿着上三角或者下三角形的方向来做.一刷一次ac,但是还没开始注意codestyle的问题,需要再刷一遍. class Solution { public: int islandPerime
A. Arpa’s hard exam and Mehrdad’s naive cheat time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output There exists an island called Arpa’s land, some beautiful girls live there, as ugly ones do. Me
Description The Romans have attacked again. This time they are much more than the Persians but Shapur is ready to defeat them. He says: "A lion is never afraid of a hundred sheep". Nevertheless Shapur has to find weaknesses in the Roman army to
