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: 第一次写的时候没有考虑到数组元素有可能重合的问题
1 public class Solution { 2 public int firstMissingPositive(int[] A) { 3 int shouldbe = 1; 4 int store = 0; 5 java.util.Arrays.sort(A); 6 for (int elem : A) { 7 if (elem > 0) { 8 if (elem == store) continue; 9 else if (elem == shouldbe) { 10 shouldbe++; 11 store = elem; 12 } 13 else break; 14 } 15 } 16 return shouldbe; 17 } 18 }
Leetcode: First Missing Positive,布布扣,bubuko.com
Leetcode: First Missing Positive
原文：http://www.cnblogs.com/EdwardLiu/p/3811206.html