41. First Missing Positive
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
解题视频,视频说先桶排序然后进行遍历求解
func firstMissingPositive(nums []int) int {
if len(nums) == 0 {
return 1
}
lg := len(nums)
for i := range nums {
for nums[i] > 0 && nums[i] < lg && nums[nums[i]-1] != nums[i] {
nums[nums[i]-1], nums[i] = nums[i], nums[nums[i]-1]
}
}
for i, v := range nums {
if i+1 != v {
return i + 1
}
}
return lg + 1
}