Formatted question description: https://leetcode.ca/all/945.html

945. Minimum Increment to Make Array Unique (Medium)

Given an array of integers A, a move consists of choosing any A[i], and incrementing it by 1.

Return the least number of moves to make every value in A unique.

 

Example 1:

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

Example 2:

Input: [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 with 5 or less moves that it is impossible for the array to have all unique values.

 

Note:

  1. 0 <= A.length <= 40000
  2. 0 <= A[i] < 40000
 

Related Topics:
Array

Solution 1.

// OJ: https://leetcode.com/problems/minimum-increment-to-make-array-unique/

// Time: O(N)
// Space: O(1)
class Solution {
public:
    int minIncrementForUnique(vector<int>& A) {
        sort(A.begin(), A.end());
        int ans = 0;
        for (int i = 1; i < A.size(); ++i) {
            if (A[i] > A[i - 1]) continue;
            ans += A[i - 1] + 1 - A[i];
            A[i] = A[i - 1] + 1;
        }
        return ans;
    }
};

Java

class Solution {
    public int minIncrementForUnique(int[] A) {
        if (A == null || A.length <= 1)
            return 0;
        int increments = 0;
        Arrays.sort(A);
        int curValue = A[0];
        int length = A.length;
        for (int i = 1; i < length; i++) {
            curValue = Math.max(curValue + 1, A[i]);
            increments += curValue - A[i];
        }
        return increments;
    }
}

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