217. Contains Duplicate

https://leetcode.com/problems/contains-duplicate

• CTCI 1.1 Is Unique

Python

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        seem = set()
        for num in nums:
            if num in seem:
                return True
            seem.add(num)
        return False

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        return len(nums) != len(set(nums))

Go

func containsDuplicate(nums []int) bool {
    seem := make(map[int]bool)
    for _, num := range nums {
        if seem[num] {
            return true
        }
        seem[num] = true
    }
    return false
}

Rust

use std::collections::HashSet;

impl Solution {
    pub fn contains_duplicate(nums: Vec<i32>) -> bool {
        let mut seen = HashSet::new();
        for num in nums {
            if seen.contains(&num) {
                return true;
            }
            seen.insert(num);
        }
        false
    }
}