Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025  385 = 2640. Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.…

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target, where index1 m…

Given a Binary Search Tree and a target number, return true if there exist two elements in the BST such that their sum is equal to the given target. Example 1: Input: 5 / \ 3 6 / \ \ 2 4 7 Target = 9 Output: True Example 2: Input: 5 / \ 3 6 / \ \ 2 4…

Problem Description: Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example: Given…

很简单.没什么好说的.但是在阿里实习的第四面的时候居然问到了. 大意是给出一组无序数列和目标数Z,在无序数列中找到X和Y,使得X+Y=Z. 有两种方法: 一种是排序后,同时首尾搜索.时间复杂度为O(nlgn) + O(n) = O(nlgn).空间复杂度为O(1) 另一种是把公式转换为X = Z-Y. 从数列从头搜到尾,每个数假设为Y,因此可以得到X,找到X是否在序列中.时间复杂度为O(n),空间复杂度为O(n) 主要学习了STL的find_if.binary_search.和sort函数.更详…

基础的动态规划...数塔取数问题. 状态转移方程: dp[i][j] = num[i][j] + max(dp[i+1][j],dp[i+1][j+1]);…

直接python搞过.没啥好办法.看了下别人做的,多数也是大数乘法搞过. 如果用大数做的话,c++写的话,fft优化大数乘法,然后快速幂一下就好了.…

题目来源:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=3&page=show_problem&problem=44  Maximum Sum  Background A problem that is simple to solve in one dimension is often much more difficult to solve in more th…

题目连接 http://poj.org/problem?id=1564 Sum It Up Description Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t = 4, n = 6, and the list is [4, 3, 2, 2, 1, 1], then…

转自  http://tech-wonderland.net/blog/summary-of-ksum-problems.html 前言: 做过leetcode的人都知道, 里面有2sum, 3sum(closest), 4sum等问题, 这些也是面试里面经典的问题, 考察是否能够合理利用排序这个性质, 一步一步得到高效的算法. 经过总结, 本人觉得这些问题都可以使用一个通用的K sum求和问题加以概括消化, 这里我们先直接给出K Sum的问题描述和算法(递归解法), 然后将这个一般性的方法套用…