InterviewBit Problems   First Missing Integer : Unsolved

About the First Missing Integer : Unsolved category (1)
Easiest method O(n) and O(1) time (1)
Why am i getting TLE for this , its O(n) only no? (2)
Error with compiler (2)
There is some issue with the compiler (1)
O(nlogn) and constant space (1)
Runtime error don't know why (2)
Simplest Solution-> Time:O(nlogn) Space:O(1) (1)
Why is this code not working while working fine in other IDE? (1)
How is the solution not working? (3)
What's wrong failing on a testcase (2)
Did in O(nlogn) time by sorting (1)
Fastest Solution from Complete Solution section exceeds the time limit (1)
Wrong TestCase for the Program! (1)
What's wrong in this code? It's giving run time error for the below testcase although when i checked i other platform it was working fine (1)
Short and easy to understand solution (2)
Solution in O(n) time and constant space (3)
Why Runtime Error ? Counting frequencies as negative numbers (2)
Why I am getting a runtime error in this solution (2)
Check this test case please (2)
Why is this solution wrong? pls help (2)
Why am I getting a runtime error here? (1)
How is this not a solution? (2)
Easy cpp code ...very very easy to understand (3)
Easy approach C++ (2)
What's wrong with this solu? (1)
Easy Solution O(n) and O(1) (1)
Simple Approach...Showing WA (1)
Why my code showing RTE (1)
Runtime error in cpp solution (1)