【一天一大 lee】存在重复元素 (难度:简单) - Day20201213

输入: [1,2,3,1]
输出: true

输入: [1,2,3,4]
输出: false

输入: [1,1,1,3,3,4,3,2,4,2]
输出: true

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    return nums.length !== new Set(nums).size
}

var containsDuplicate = function(nums) {
    let map = new Map()
    for (let i = 0; i < nums.length; i++) {
        if (map.has(nums[i])) return false
        map.set(nums[i])
    }
    return true
}

var containsDuplicate = function(nums) {
    nums.sort((a, b) => a - b)
    for (let i = 1; i < nums.length; i++) {
        if (nums[i - 1] === nums[i]) return false
    }
    return true
}