2465. 不同的平均值数目c

int cmp(const void* a,const void* b){
    return *(int*)a-*(int*)b;
}

int distinctAverages(int* nums, int numsSize) {
    if(numsSize <=2) return 1;
    qsort(nums,numsSize,sizeof(int),cmp);
    int use[300]={0};
    int head=0,tail=numsSize-1,count=0;
    while(head<=tail){
        int t=nums[head]+nums[tail];
        if(use[t]==0){
            use[t]=1;
            count++;
        }
        head++;
        tail--;
    }
    return count;
}