503. Next Greater Element II 下一个更大元素

 Given a circular array (the next element of the last element is the first element of the array), print the Next Greater Number for every element. The Next Greater Number of a number x is the first greater number to its traversing-order next in the array, which means you could search circularly to find its next greater number. If it doesn't exist, output -1 for this number.

Example 1:

Input: [1,2,1]
Output: [2,-1,2]
Explanation: The first 1's next greater number is 2; 
The number 2 can't find next greater number; 
The second 1's next greater number needs to search circularly, which is also 2.

Note: The length of given array won't exceed 10000. 


给定一个循环数组（最后一个元素的下一个元素是数组的第一个元素），为每个元素输出Next Greater Number。下一个更大数字x是数组中第一个更大的数字，这意味着您可以循环搜索以找到下一个更大的数字。如果不存在，则输出-1。

  1. /**
  2.  * @param {number[]} nums
  3.  * @return {number[]}
  4.  */
  5. var nextGreaterElements = function (nums) {
  6.     let res = [];
  7.     res.length = nums.length;
  8.     res.fill(-1);
  10.     let stack = [];
  11.     let index = 0;
  12.     while (index < nums.length * 2) {
  13.         let cur = nums[index % nums.length];
  14.         while (stack.length > 0 && nums[stack[stack.length - 1]] < cur) {
  15.             res[stack.pop()] = cur;
  16.         }
  17.         if (index < nums.length) stack.push(index);
  18.         index++
  19.     }
  20.     return res;
  21. };
  23. //let nums = [2, 1, 1, 3];
  24. let nums = [1, 2, 1];
  25. let res = nextGreaterElements(nums);
  26. console.log(res);






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原文地址：https://www.cnblogs.com/xiejunzhao/p/8146584.html