This Leetcode Contains a Duplicate problem solution 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.

Leetcode Contains Duplicate problem solution


Problem solution in Python.

def containsDuplicate(self, nums: List[int]) -> bool:
        s=set()
        for ele in nums:
            if ele in s:
                return True
            else:
                s.add(ele)



Problem solution in Java.

public class Solution {
    public boolean containsDuplicate(int[] nums) {
        int i;
        Arrays.sort(nums);
        for(i=0;i<nums.length-1;i++)
        {
            if(nums[i]==nums[i+1])
            return true;
        }
        return false;
    }
}


Problem solution in C++.

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        unordered_map<int,int> count;
        for(auto i:nums)
            if(++count[i]>1) return true;
        return false;
    }
};


Problem solution in C.

int compare(const void* a, const void* b)
{
    int l=*(int*)a;
    int p=*(int*)b;
    return (l-p);
}

bool containsDuplicate(int* nums, int numsSize) {
    qsort(nums,numsSize,sizeof(int),compare);
    
    for(int i=0;i<numsSize-1;i++)
    {
        if(nums[i]==nums[i+1])
        {
            return true;
        }
       // printf("%d==%d\n",nums[i],nums[i+1]);
    }
    return false;
}