169. 多数元素

/**
 * @param {number[]} nums
 * @return {number}
 */
var majorityElement = function (nums) {
  const len = nums.length
  if (len === 1) {
    return nums[0]
  }
  const count = Math.floor(len / 2)

  const map = new Map()
  for (let i = 0; i < len; i++) {
    if (map.has(nums[i]) && map.get(nums[i]) + 1 > count) {
      return nums[i]
    } else if (map.has(nums[i])) {
      map.set(nums[i], map.get(nums[i]) + 1)
    } else {
      map.set(nums[i], 1)
    }
  }
}