바위타는 두루미

문제 임시 변수를 사용하지 않고 숫자를 교환하는 함수를 작성하라. 해법 이 문제는 두 수중 하나의 수에 그 둘의 '차이'를 가지고 있도록 하면 해결할 수 있는 문제이다. 숫자 a, b가 있다면 a = a-b 를 통해 a가 차이를 가지고 있도록 하고, b = a +b 를 통해 a가 된다. 그리고 다시 a = b -a를 통해 a 는 b가 된다. a = 9 b = 4라고 할때 a = a- b ( a = 9 - 4 =5) b = a+b (b = 5+4 =9) a = b-a ( a = 9-5 =4) 비트로도 같은 연산이 가능하다. 이러면 정수 이외의 자료형에서도 동작한다는 이점이 있다. a = a^b b = a^b a = a^b

300. Longest Increasing Subsequence Given an unsorted array of integers, find the length of longest increasing subsequence. Example: Input: [10,9,2,5,3,7,101,18] Output: 4 Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4. Note: There may be more than one LIS combination, it is only necessary for you to return the length. Your algorithm should run in O(n2)..

322. Coin Change You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. Example 1: Input: coins = [1, 2, 5], amount = 11 Output: 3 Explanation: 11 = 5 + 5 + 1 Example 2: Input: coins = [2], a..

62. Unique Paths A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below). How many possible unique paths are there? Above is a 7 x 3 grid. How many possible unique paths are there? Note:..

55. Jump Game Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if you are able to reach the last index. Example 1: Input: [2,3,1,1,4] Output: true Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index. Example 2: Input: [3,2,1,0,4] O..

33. Search in Rotated Sorted Array Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]). You are given a target value to search. If found in the array return its index, otherwise return -1. You may assume no duplicate exists in the array. Your algorithm's runtime complexity must be in the order of O(lo..

56. Merge Intervals Given a collection of intervals, merge all overlapping intervals. Example 1: Input: [[1,3],[2,6],[8,10],[15,18]] Output: [[1,6],[8,10],[15,18]] Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6]. Example 2: Input: [[1,4],[4,5]] Output: [[1,5]] Explanation: Intervals [1,4] and [4,5] are considered overlapping. NOTE: input types have been changed on Ap..

34. Find First and Last Position of Element in Sorted Array Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be in the order of O(log n). If the target is not found in the array, return [-1, -1]. Example 1: Input: nums = [5,7,7,8,8,10], target = 8 Output: [3,4] Example 2: Input: nums..

162. Find Peak Element A peak element is an element that is greater than its neighbors. Given an input array nums, where nums[i] ≠ nums[i+1], find a peak element and return its index. The array may contain multiple peaks, in that case return the index to any one of the peaks is fine. You may imagine that nums[-1] = nums[n] = -∞. Example 1: Input: nums = [1,2,3,1] Output: 2 Explanation: 3 is a pe..

347. Top K Frequent Elements Given a non-empty array of integers, return the kmost frequent elements. Example 1: Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Example 2: Input: nums = [1], k = 1 Output: [1] Note: You may assume k is always valid, 1 ≤ k ≤ number of unique elements. Your algorithm's time complexity must bebetter than O(n log n), where n is the array's size. 1 solution class Sol..