fmp

fmp.cpp

class Solution {
private:
    bool hash[500001] = {0, };
public:
    int firstMissingPositive(vector<int>& nums) {
        int cnt;
        for (int i=0; i<nums.size(); i++){
            if(nums[i] <= 0 || nums[i] > nums.size()) continue;
            else hash[nums[i]] = true;
        }
        for (int i=1; i<500000; i++){
            if(!hash[i]) return i;
        }
        return nums.size() + 1;
    }
};