Given a non-negative integer N, find the largest number that is less than or equal to Nwith monotone increasing digits.
(Recall that an integer has monotone increasing digits if and only if each pair of adjacent digits x and y satisfy x <= y.)
Example 1:
Input: N = 10 Output: 9
Example 2:
Input: N = 1234 Output: 1234
Example 3:
Input: N = 332 Output: 299
Note: N is an integer in the range [0, 10^9].
给定一个非负整数 N，找出小于或等于 N 的最大的整数，同时这个整数需要满足其各个位数上的数字是单调递增。
（当且仅当每个相邻位数上的数字 x 和 y 满足 x <= y 时，我们称这个整数是单调递增的。）
示例 1:
输入: N = 10 输出: 9
示例 2:
输入: N = 1234 输出: 1234
示例 3:
输入: N = 332 输出: 299
说明: N 是在 [0, 10^9] 范围内的一个整数。
Runtime: 8 ms Memory Usage: 19 MB
1 class Solution {
2 func monotoneIncreasingDigits(_ N: Int) -> Int {
3 var str:String = String(N)
4 var arrInt:[Int] = Array(str).map{$0.ascii}
5 var n:Int = str.count
6 var j:Int = n
7 for i in stride(from:n - 1,to:0,by:-1)
8 {
9 if arrInt[i] >= arrInt[i - 1]
10 {
11 continue
12 }
13 arrInt[i - 1] -= 1
14 j = i
15 }
16 for i in j..<n
17 {
18 arrInt[i] = 57
19 }
20 var arrChar:[Character] = arrInt.map{$0.ASCII}
21 return Int(String(arrChar)) ?? 0
22 }
23 }
24
25 //Character扩展
26 extension Character
27 {
28 //Character转ASCII整数值(定义小写为整数值)
29 var ascii: Int {
30 get {
31 return Int(self.unicodeScalars.first?.value ?? 0)
32 }
33 }
34 }
35
36 //Int扩展
37 extension Int
38 {
39 //Int转Character,ASCII值(定义大写为字符值)
40 var ASCII:Character
41 {
42 get {return Character(UnicodeScalar(self)!)}
43 }
44 }