[LeetCode41]找到一段连续正整数中丢失的数

class Solution {
public:
    int firstMissingPositive(vector& nums) {
        int len=num.size();
		if(len==0) return 1;
		for(int i=0; i0&&nums[i]<=len&&nums[nums[i]-1]!=nums[i])
			{
				int tmp=num[nums[i]-1];
				num[nums[i]-1]=num[i];
				num[i]=tmp;
				i--;
			}
		}
		for(int i=0; i