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.
Solution:
public int firstMissingPositive(int[] nums) { for (int i = 0; i < nums.length; i++) { while (nums[i] > 0 && nums[i] < nums.length && nums[i] != nums[nums[i] - 1]) { int temp = nums[i]; nums[i] = nums[temp - 1]; nums[temp - 1] = temp; } } for (int i = 0; i < nums.length; i++) { if (nums[i] != i + 1) { return i + 1; } } return nums.length + 1; }新闻热点
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