[Swift]LeetCode556. 下一个更大元素 III | Next Greater Element III

Given a positive 32-bit integer n, you need to find the smallest 32-bit integer which has exactly the same digits existing in the integer nand is greater in value than n. If no such positive 32-bit integer exists, you need to return -1.

Example 1:

Input: 12
Output: 21 

Example 2:

Input: 21
Output: -1

示例 1:

输入: 12
输出: 21

示例 2:

输入: 21
输出: -1

Runtime: 8 ms

Memory Usage: 18.8 MB

 1 class Solution {
 2     func nextGreaterElement(_ n: Int) -> Int {
 3         var str:String = String(n)
 4         var arr:[Character] = Array(str)
 5         var len:Int = str.count
 6         var i:Int = len - 1
 7         while(i > 0)
 8         {
 9             if arr[i] > arr[i - 1] {break}
10             i -= 1
11
12         }
13         if i == 0 {return -1}
14         for j in (i...(len - 1)).reversed()
15         {
16             if arr[j] > arr[i - 1]
17             {
18                 arr.swapAt(j,i - 1)
19                 break
20             }
21         }
22         var str2 = String(arr[0..<i])
23         str2  += String(arr[i..<arr.count].sorted(by:<))
24         var res:Int = Int(str2)!
25         return res > 2147483647 ? -1 : Int(res)
26     }
27 }

原文地址：https://www.cnblogs.com/strengthen/p/10415232.html