217. Contains Duplicate
給定一個整數數組 nums，如果數組中任何值至少出現兩次，返回 true；如果每個元素都是唯一的，返回 false。
範例：
輸入：nums = [1, 2, 3, 1] 輸出：true
Python
class Solution:
def containsDuplicate(self, nums: List[int]) -> bool:
seen = set()
for num in nums:
if num in seen:
return True
seen.add(num)
return False
31.87MB, 427ms
C++
#include <vector>
#include <unordered_set>
using namespace std;
class Solution {
public:
bool containsDuplicate(vector<int>& nums) {
unordered_set<int> seen;
for (int num : nums) {
if (seen.find(num) != seen.end()) {
return true;
}
seen.insert(num);
}
return false;
}
};
73.45MB, 90ms
Javascript
/**
* @param {number[]} nums
* @return {boolean}
*/
var containsDuplicate = function(nums) {
const seen = new Set();
for (const num of nums) {
if (seen.has(num)) {
return true;
}
seen.add(num);
}
return false;
};
63.MB, 73ms
