Given an unsorted integer array, find the smallest missing positive integer.
Example 1:
Input: [1,2,0]
Output: 3
Example 2:
Input: [3,4,-1,1]
Output: 2
Example 3:
Input: [7,8,9,11,12]
Output: 1
Note:
Your algorithm should run in O(n) time and uses constant extra space.
题意：
给定无序数组，找出第一个未出现的正整数。
Solution1:
code
[leetcode]41. First Missing Positive第一个未出现的正数
原文：https://www.cnblogs.com/liuliu5151/p/10730091.html