14. First Position of Target [easy] For a given sorted array (ascending order) and a targetnumber, find the first index of this number in O(log n) time complexity. If the target number does not exist in the array, return -1. Example If the array is […

60. Search Insert Position [easy] Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume NO duplicates in the array. Example [1,3,5,6],…

121. Best Time to Buy and Sell Stock[easy] Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an…

448. Find All Numbers Disappeared in an Array[easy] Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements of [1, n] inclusive that do not appear in this array. Coul…

1. Two Sum[easy] 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 nums…

167. Two Sum II - Input array is sorted[easy] 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…

283. Move Zeroes[easy] Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements. For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3…

219. Contains Duplicate II[easy] Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k. 错误解法: class Solut…

657. Judge Route Circle[easy] Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place. The move sequence is represented by a string. And each m…

2. Trailing Zeros[easy] Write an algorithm which computes the number of trailing zeros in n factorial. Have you met this question in a real interview? Yes Example 11! = 39916800, so the out should be 2 Challenge O(log N) time 解法一: class Solution { /*…