【leetcode】特殊数组的特征值

int cmp(const void* a,const void* b){
    return *(int*)a-*(int*)b;
}
int specialArray(int* nums, int numsSize){
    qsort(nums,numsSize,sizeof(int),cmp);
    if(nums[numsSize-1]<0) return 0;
    for(int i=numsSize; i>0; i--){
        if(nums[numsSize-i]>=i && (i==numsSize || nums[numsSize-i-1]<i))
            return i;
    }
    return -1;
}