503.next-greater-element-ii.js

/*
 * @lc app=leetcode.cn id=503 lang=javascript
 *
 * [503] Next Greater Element II
 */

// @lc code=start
/**
 * @param {number[]} nums
 * @return {number[]}
 * [ 3, 2, 1, 4, 3, 2, 1, 4]
 * 
 * // 索引
 * [ 0]
 * 
 * [ -1, -1, -1, -1, -1, -1, -1, -1]
 * [ -1, -1, -1, -1]
 * 
 */
var nextGreaterElements = function(nums) {
    nums = nums.concat(nums);
    let len = nums.length;
    let oldLen = len / 2;
    let stack = [];
    let ans = new Array(oldLen).fill(-1);
    for (let i = 0; i < len; i++) {
        let current = nums[i];

        while (stack.length > 0 && current > nums[stack[stack.length - 1]]) {
            let topIndex = stack[stack.length - 1];
            ans[topIndex % oldLen] = current;
            stack.pop();
        }
        stack.push(i)
    }
    return ans;
};
// @lc code=end