You are given a 0-indexed integer array nums. In one operation, you may do the following:
Choose two integers in nums that are equal.
Remove both integers from nums, forming a pair.
The operation is done on nums as many times as possible.
Return a 0-indexed integer array answer of size 2 where answer[0] is the number of pairs that are formed and answer[1] is the number of leftover integers in nums after doing the operation as many times as possible.
Example 1:
Input: nums = [1,3,2,1,3,2,2]
Output: [3,1]
Explanation:
Form a pair with nums[0] and nums[3] and remove them from nums. Now, nums = [3,2,3,2,2].
Form a pair with nums[0] and nums[2] and remove them from nums. Now, nums = [2,2,2].
Form a pair with nums[0] and nums[1] and remove them from nums. Now, nums = [2].
No more pairs can be formed. A total of 3 pairs have been formed, and there is 1 number leftover in nums.
Example 2:
Input: nums = [1,1]
Output: [1,0]
Explanation: Form a pair with nums[0] and nums[1] and remove them from nums. Now, nums = [].
No more pairs can be formed. A total of 1 pair has been formed, and there are 0 numbers leftover in nums.
Example 3:
Input: nums = [0]
Output: [0,1]
Explanation: No pairs can be formed, and there is 1 number leftover in nums.
/** * Note: The returned array must be malloced, assume caller calls free(). */int*numberOfPairs(int*nums,intnumsSize,int*returnSize){intcount[101]={0};for(inti=0;i<numsSize;i++){count[nums[i]]++;}intsum=0;for(inti=0;i<101;i++){sum+=count[i]>>1;}int*ans=malloc(sizeof(int)*2);ans[0]=sum;ans[1]=numsSize-sum*2;*returnSize=2;returnans;}