ARTS第一周

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = {}
    for (i = 0; i < nums.length; i++) {
        if (map[nums[i]] !== undefined) return [map[nums[i]], i];
        map[target - nums[i]] = i;
    }
};