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Given an array nums of positive integers. Your task is to select some subset of nums, multiply each element by an integer and add all these numbers. T 阅读全文
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You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). You have to rotate the image in-place, which means 阅读全文
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Given a rows x cols binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. Example 1: Input: matri 阅读全文
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There are a row of n houses, each house can be painted with one of the k colors. The cost of painting each house with a certain color is different. Yo 阅读全文
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There are a row of n houses, each house can be painted with one of the three colors: red, blue or green. The cost of painting each house with a certai 阅读全文
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Given two strings s and t, you want to transform string s into string t using the following operation any number of times: Choose a non-empty substrin 阅读全文
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Given an integer array arr, remove a subarray (can be empty) from arr such that the remaining elements in arr are non-decreasing. A subarray is a cont 阅读全文
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I have run into 2 different problems that can be solved using binary lifting. Then there is second thread's tree basics youtube video that talks about 阅读全文
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Given an array arr that represents a permutation of numbers from 1 to n. You have a binary string of size n that initially has all its bits set to zer 阅读全文
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Given an integer n and an integer array rounds. We have a circular track which consists of n sectors labeled from 1 to n. A marathon will be held on t 阅读全文