0496-next-greater-element-i.js

/**
 * 496. Next Greater Element I
 * https://leetcode.com/problems/next-greater-element-i/
 * Difficulty: Easy
 *
 * The next greater element of some element x in an array is the first greater element
 * that is to the right of x in the same array.
 *
 * You are given two distinct 0-indexed integer arrays nums1 and nums2, where nums1 is
 * a subset of nums2.
 *
 * For each 0 <= i < nums1.length, find the index j such that nums1[i] == nums2[j] and
 * determine the next greater element of nums2[j] in nums2. If there is no next greater
 * element, then the answer for this query is -1.
 *
 * Return an array ans of length nums1.length such that ans[i] is the next greater
 * element as described above.
 */

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number[]}
 */
var nextGreaterElement = function(nums1, nums2) {
  return nums1.map(n => {
    let index = nums2.indexOf(n);
    while (nums2[index] <= n) {
      index++;
    }
    return index >= nums2.length ? -1 : nums2[index];
  });
};