Given an integer matrix, find a submatrix where the sum of numbers is zero. Your code should return the coordinate of the left-up and right-down number. Have you met this question in a real interview? Yes Example Given matrix [ [1 ,5 ,7], [3 ,7 ,-8],…

Naive solution is O(n^4). But on 1 certain dimension, naive O(n^2) can be O(n) by this well-known equation: sum[i..j] = sum[0..j] - sum[0..i]. And pls take care of several corner cases. class Solution { public: /** * @param matrix an integer matrix *…

Maximal Subarray Sum : O(n) scan-and-update dynamic programming, https://en.wikipedia.org/wiki/Maximum_subarray_problem, https://leetcode.com/problems/maximum-subarray Maximal Submatrix Sum: given 2-D matrix, find the submatrix whose sum is largestwe…

和为零的子矩阵 给定一个整数矩阵,请找出一个子矩阵,使得其数字之和等于0.输出答案时,请返回左上数字和右下数字的坐标. 样例 给定矩阵 [ [1 ,5 ,7], [3 ,7 ,-8], [4 ,-8 ,9], ] 返回 [(1,1), (2,2)] 挑战 O(n3) 时间复杂度 解题 直接暴露求解,时间复杂度O(N2*M2 ) public class Solution { /** * @param matrix an integer matrix * @return the coordinat…

K SUM My Submissions http://www.lintcode.com/en/problem/k-sum/ 题目来自九章算法 13% Accepted Given n distinct positive integers, integer k (k <= n) and a number target. Find k numbers where sum is target. Calculate how many solutions there are? Example Given…

4 Pointer solution. Key: when moving pointers, we skip duplicated ones. Ref: https://github.com/xbz/lintcode/blob/master/4_sum/4sum.cpp class Solution { void nextUnique(vector<int> &num, size_t &j) { ]) ++j; } public: vector<vector<int…

Given an integer matrix, find a submatrix where the sum of numbers is zero. Your code should return the coordinate of the left-up and right-down number. Example Given matrix [ [1 ,5 ,7], [3 ,7 ,-8], [4 ,-8 ,9], ] return [(1,1), (2,2)] 分析: 本质上还是subarr…

Subarray Sum 原题链接:http://lintcode.com/zh-cn/problem/subarray-sum/# Given an integer array, find a subarray where the sum of numbers is zero. Your code should return the index of the first number and the index of the last number. 样例 Given [-3, 1, 2, -…

For this problem we need to learn a new trick that if your start sum up all elements in an array. When you start from a to b to sum up all elements, if the result is zero, and also the summation of all elements from index a to c ( c<=b ) is zero. The…

Given an array of integers, 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 must be less than index2. Please note that…