compiler error #pragma GCC optimize ("O1")

442

i am solving this question https://leetcode.com/problems/longest-consecutive-sequence/
my code is as follows,

class Solution {
public:
int longestConsecutive(vector& nums) {

   if(nums.empty()) return 0; 
   int n=nums.size() ;
     unordered_set<int>  s;
    int max_length = 0;
    int max = MIN_INT ; 
    int min = MAX_INT ;
    for(int i=0;i<n;i++){

             if(nums[i]>max) max=nums[i];
             if(nums[i] < min) min=nums[i];
        for(int i=0;i<n;i++){
            
                if(s.find(nums[i]) != s.end()){
                    
                        int count1=0 , count2=0 , length =0;
                    for(int j=1;j<=(nums[i]-min);j++)
                    {
                        if(s.find(nums[i]-j)  != s.end() ) count1++;
                        else break;
  
                    }
              for(int j=1;j<=(max-nums[i]);j++)
                    {
                        if(s.find(nums[i]+j)  != s.end() ) count2++;
                        else break;
      }
                length = count1 + count2 + 1;
             if(length>max_length) max_length=length;
    }            
    else  s.insert(nums[i]);  
        }
}
     return max_length ;