Question:

I am working on a problem where I need to make every value in an integer array nums unique with the minimum number of moves. In each move, I can pick an index i (where 0 <= i < nums.length) and increment nums[i] by 1.

I need to return the minimum number of moves required to achieve this.

Here are a couple of examples:

Example 1:

• Input: nums = [1, 2, 2]

• Output: 1

• Explanation: After 1 move, the array could be [1, 2, 3].

Example 2:

• Input: nums = [3, 2, 1, 2, 1, 7]

• Output: 6

• Explanation: After 6 moves, the array could be [3, 4, 1, 2, 5, 7]. It can be shown that with 5 or fewer moves, it is impossible for the array to have all unique values.

Issue:

When I sort the array and find duplicate elements using the == operator, the code does not provide the required results. However, when I change the comparison to <=, it passes all test cases. Here is the code snippet:

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){ 
    vector<int> nums={3,2,1,2,1,7}; //The given testcase
    int minIncrements = 0;
    sort(nums.begin(), nums.end());
    for (int i = 1; i < nums.size(); ++i) {
        if (nums[i] == nums[i - 1]) { //Equality operator produce incorrect
        //if (nums[i] <= nums[i - 1]) { // This works correctly
            int incrementNeeded = nums[i - 1] - nums[i] + 1; 
            nums[i] += incrementNeeded;
            minIncrements += incrementNeeded;
        }
    }
    cout<<minIncrements; //Expected to be 6 but return 2
return 0;
}

Question:

I am trying to solve a problem where I need to make every value in an integer array nums unique with the minimum number of moves. Each move increments any chosen element by 1.

When I use the condition if (nums[i] <= nums[i - 1]) in my code, it works correctly. However, when I change it to if (nums[i] == nums[i - 1]), the output is incorrect. I thought both should check for duplicate elements.

Could someone explain why using == does not work correctly, but using <= does?