## LeetCode – First Missing Positive (Java)

Given an unsorted integer array, find the first missing positive integer. For example, given [1,2,0] return 3 and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses constant space. Analysis This problem can solve by using a bucket-sort like algorithm. Let’s consider finding first missing positive and 0 first. The key fact … Read more