Algorithm
Problem Name: 217. Contains Duplicate
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Example 1:
Input: nums = [1,2,3,1] Output: true
Example 2:
Input: nums = [1,2,3,4] Output: false
Example 3:
Input: nums = [1,1,1,3,3,4,3,2,4,2] Output: true
Constraints:
1 <= nums.length <= 105-109 <= nums[i] <= 10
Code Examples
#1 Code Example with C Programming
Code -
C Programming
int cmp(const void *a, const void *b) {
return *(int *)a - *(int *)b;
}
bool containsDuplicate(int* nums, int numsSize) {
int i;
qsort(nums, numsSize, sizeof(int), cmp);
for (i = 1; i < numsSize; i ++) {
if (nums[i] == nums[i - 1]) return true;
}
return false;
}
Input
nums = [1,2,3,1]
Output
true
#2 Code Example with Java Programming
Code -
Java Programming
class Solution {
public boolean containsDuplicate(int[] nums) {
return Arrays.stream(nums).boxed().collect(Collectors.toSet()).size() < nums.length;
}
}
Input
nums = [1,2,3,1]
Output
true
#3 Code Example with Javascript Programming
Code -
Javascript Programming
const containsDuplicate = function(nums) {
const hash = {};
for (let el of nums) {
if (hash.hasOwnProperty(el)) {
return true;
} else {
hash[el] = 1;
}
}
return false;
};
Input
nums = [1,2,3,4]
Output
false
#4 Code Example with Python Programming
Code -
Python Programming
class Solution:
def containsDuplicate(self, nums):
"""
:type nums: List[int]
:rtype: bool
"""
dic=dict()
for num in nums:
if not num in dic:
dic[num]=1
else:
return True
return False
Input
nums = [1,2,3,4]
Output
false
#5 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
namespace LeetCode
{
public class _0217_ContainsDuplicate
{
public bool ContainsDuplicate(int[] nums)
{
var set = new HashSet < int>();
foreach (var num in nums)
{
if (set.Contains(num)) return true;
set.Add(num);
}
return false;
}
}
}
Input
nums = [1,1,1,3,3,4,3,2,4,2]
Output
true