LeetCode周赛#112 Q1 Minimum Increment to Make Array Unique

题目来源：https://leetcode.com/contest/weekly-contest-112/problems/minimum-increment-to-make-array-unique/

问题描述

 945. Minimum Increment to Make Array Unique

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

------------------------------------------------------------

题意

给出一个数列，每次将数列的一个元素+1称为一次“操作”。求使数列中元素互不相同的最小操作次数。

------------------------------------------------------------

思路

首先将数组排序。用cur记录数列中前一项，操作直到该项比前一项多1。如果有多个数字重复，则cur表示已经加过若干个1的前项。

------------------------------------------------------------

代码

class Solution {
public:
    int minIncrementForUnique(vector<int>& A) {
        if (A.empty())
        {
            return 0;
        }
        sort(A.begin(), A.end());
        int i, n = A.size(), cur = A[0], addi, ret = 0;
        for (i=1; i<n; i++)
        {
            addi = (cur + 1 - A[i]) > 0 ? (cur + 1 - A[i]) : 0;
            ret += addi;
            cur = A[i] + addi;
        }
        return ret;
    }
};