LeetCode 217.存在重复元素【力扣——C/C++/Python三种编程语言题解】

bool containsDuplicate(int* nums, int numsSize){
  int i = 0;
  int _callback(const void* val1, const void* val2)
  {
    return (*(int*)val1 - *(int*)val2);
  }
  /*调用库函数qsort，自己写排序可能会超时*/
  qsort(nums, numsSize, sizeof(int), _callback);
  for(i = 1; i < numsSize; i++)
  {
    if(nums[i - 1] == nums[i])
    {
      return true;
    }
  }
  return false;
}

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
    set<int> s;
    for(vector<int>::iterator it = nums.begin(); it != nums.end(); it++)
    {
      s.insert(*it);
    }
    if(s.size() < nums.size())
    {
      return true;
    }
    return false;
    }
};

class Solution(object):
    def containsDuplicate(self, nums):
    return (len(set(nums)) != len(nums))