[ 算法 ] Majority Element

Majority Element

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

You may assume that the array is non-empty and the majority element always exist in the array.

/**
* @param {number[]} nums
* @return {number}
*/
var majorityElement = function(nums) {
var ret = [];
var max = -1;
var key = -1;
for(var i = 0 ; i< nums.length; i ++){
if(ret[nums[i]]){
ret[nums[i]] = ret[nums[i]] + 1;
}else{
ret[nums[i]] = 1;
}
if(ret[nums[i]] > max){
max = ret[nums[i]];
key = nums[i];
}
}
if(max - (nums.length - max )){
return key;
}else{
return -1;
}
};