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
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
环形版本,就是在两倍长度的数组上重复之前那题
Code
classSolution {publicint[] nextGreaterElements(int[] nums) {int[] res =newint[nums.length];Stack<Integer> stack =newStack<>();Arrays.fill(res,-1);int len =nums.length;for (int i =0; i <2* len; i++) {int num = nums[i % len];while (!stack.isEmpty() && nums[stack.peek()] < num) { res[stack.pop()] = num; }if (i < len) {stack.push(i); } }return res; }}