本题的模型是典型的求第k小问题,这个问题有2个不一样的点,一是任意选出2个数,不能是同一个,二是这个题有负数,那我们在原有的基础上就需要特判这两点,经典模型是2个数组相乘,此处是1个,那么一样可以枚举每一个数,计算比该数小的数的数量,运用容斥,将重复的去掉即可,第一个问题就解决了,假设要判断的数是a,当前枚举到的数是b,第二个问题就是有0有负数有正数,b=0的情况很简单,若a大于0,那么一定所有的数乘a都小于a,直接累加即可,b=正数的情况就比较经典,二分查找比a/b小的数,累加即可,b=负数呢…

题目 两次二分 首先对ans进行二分,在\([-10^{18},10^{18}]\)之间 考虑怎么check 对于每个ans,枚举每个\(a_i\),二分查找有几个\(a_j\),使得\(a_i\times a_j<ans\) 对于每对合法的\((a_i,a_j)\),枚举到\(a_i\)和\(a_j\)的时候都被找了一遍,所以最后应该除以2来去重 因为不能出现\(a_i=a_j\),所以返回的时候要把\(i=j\)的情况去掉 两个数组a,b 将输入的数在a中按升序排序,在b中按降序排 在第二次…

You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k. Define a pair (u,v) which consists of one element from the first array and one element from the second array. Find the k pairs (u1,v1),(u2,v2) ...(uk,vk) wit…

Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1:Given words = ["bat", "tab", "cat"]Ret…

#24. Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify t…

1. Description Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1: Given words = ["bat", "tab", &qu…

In the secret book of ACM, it’s said: “Glory for those who write short ICPC problems. May they live long, and never get Wrong Answers” . Everyone likes problems with short statements. Right? Let’s have five positive numbers: X1,X2,X3,X4,X5. We can fo…

24. Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. For example,Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the…

Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1:Given words = ["bat", "tab", "cat"]Ret…

336-Palindrome Pairs Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1: Given words = ["bat", "tab"…

Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1:Given words = ["bat", "tab", "cat"]Ret…

Calculating Stereo Pairs Written by Paul BourkeJuly 1999 Introduction The following discusses computer based generation of stereo pairs as used to create a perception of depth. Such depth perception can be useful in many fields, for example, scientif…

Create side-by-side stereo pairs in the Unity game engine Paul BourkeDecember 2008 Sample Island project: Island_stereo.zip See also: Using Unity in the iDome In the following I will outline one way of creating stereo pairs within the Unity game engi…

先看一段简单的代码: local mytable = { , , aa = "abc", subtable = {}, , } --for循环1 print("for --- index") ,#mytable do print(i) end --for循环2 print("for ---- index-value") for i,v in ipairs(mytable) do print(i,v) end --for循环3 print(&quo…

http://acm.hust.edu.cn/vjudge/contest/view.action?cid=109329#problem/B    全题在文末. 题意:在a,b中(a,b<=n)(1 ≤ n ≤ 1014),有多少组(a,b)  (a<b)满足lcm(a,b)==n; 先来看个知识点: 素因子分解:n = p1 ^ e1 * p2 ^ e2 *..........*pn ^ en for i in range(1,n): ei 从0取到ei的所有组合 必能包含所有n的因子. 现…

本题的特点在于两个list nums1和nums2都是已经排序好的.本题如果把所有的(i, j)组合都排序出来,再取其中最小的K个.其实靠后的很多组合根本用不到,所以效率较低,会导致算法超时.为了简便,把nums1和nums2里面的元素写成A1,A2,...,A5, B1,...,B5. 维护一个最小堆.并逐渐往里面push and pop元素. 注意以下几点:1. 如果(Ai, Bj)大于堆顶的元素,那么没有比较把(Ai, Bj)和它之后的元素Push进堆.2. 为了便于管理,解法里其实只维护…

按边长从小到大排序...再逐个加入(就像MST一样)最先联通的点之间最长路径中的最小值就是新加入的边的长.... Count The Pairs Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 266    Accepted Submission(s): 140 Problem Description   With the 60th…

B - Pairs Forming LCM Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1236 Description Find the result of the following code: long long pairsFormLCM( int n ) {    long long res = 0;    for( in…

Given a linked list, swap every two adjacent nodes and return its head.   Example Given 1->2->3->4, you should return the list as 2->1->4->3. Challenge Your algorithm should use only constant space. You may not modify the values in the l…

For an array A, if i < j, and A [i] > A [j], called (A [i], A [j]) is a reverse pair.return total of reverse pairs in A. ExampleGiven A = [2, 4, 1, 3, 5] , (2, 1), (4, 1), (4, 3) are reverse pairs. return 3 这道题跟LeetCode上的那道Count of Smaller Numbers A…

Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the va…

For an array A, if i < j, and A [i] > A [j], called (A [i], A [j]) is a reverse pair.return total of reverse pairs in A.   Example Given A = [2, 4, 1, 3, 5] , (2, 1), (4, 1), (4, 3) are reverse pairs. return 3 分析: 如果用两个for loop,非常简单. public class So…

题目地址:http://blog.csdn.net/shiyuankongbu/article/details/10004443 /* 题意:在i前面找回文子串,在i后面找回文子串相互配对,问有几对 DP:很巧妙的从i出发向两头扩展判断是否相同来找回文串 dpr[i] 代表记录从0到i间的回文子串的个数,dpl[i] 代表记录i之后的回文子串个数 两两相乘就行了 详细解释:http://blog.csdn.net/shiyuankongbu/article/details/10004443 */…

Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1: Given words = ["bat", "tab", "cat"] R…

http://www.practice.geeksforgeeks.org/problem-page.php?pid=387 Find sum of different corresponding bits for all pairs We define f (X, Y) as number of different corresponding bits in binary representation of X and Y. For example, f (2, 7) = 2, since b…

http://lightoj.com/volume_showproblem.php?problem=1236 Pairs Forming LCM Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1236 Description Find the result of the following code: long long pairs…

标准库提供了集中迭代器,包括迭代文件每行的(io.lines),迭代table元素的(pairs),迭代数组元素的(ipairs),迭代字符串中单词的 (string.gmatch)等等.LUA手册中对与pairs,ipairs解释如下: ipairs (t) Returns three values: an iterator function, the table t, and 0, so that the construction for i,v in ipairs(t) do body e…

Cube digit pairs Each of the six faces on a cube has a different digit (0 to 9) written on it; the same is done to a second cube. By placing the two cubes side-by-side in different positions we can form a variety of 2-digit numbers. For example, the…

https://leetcode.com/problems/palindrome-pairs/ Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1: Given words =…

You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k. 给你两个数组nums1和nums2,这两个数组都是递增排列的,还给你一个整数k. Define a pair (u,v) which consists of one element from the first array and one element from the second array. 定义一个pa…