Solution (leetcode-in-java 1.23 API)

java.lang.Object
- g0401_0500.s0481_magical_string.Solution

```
public class Solution
extends Object
```
481 - Magical String.
Medium

A magical string s consists of only '1' and '2' and obeys the following rules:
- The string s is magical because concatenating the number of contiguous occurrences of characters '1' and '2' generates the string s itself.
The first few elements of s is s = "1221121221221121122\u2026\u2026". If we group the consecutive 1’s and 2’s in s, it will be "1 22 11 2 1 22 1 22 11 2 11 22 ......" and the occurrences of 1’s or 2’s in each group are "1 2 2 1 1 2 1 2 2 1 2 2 ......". You can see that the occurrence sequence is s itself.

Given an integer n, return the number of 1’s in the first n number in the magical string s.

Example 1:

Input: n = 6

Output: 3

Explanation: The first 6 elements of magical string s is “122112” and it contains three 1’s, so return 3.

Example 2:

Input: n = 1

Output: 1

Constraints:
- 1 <= n <= 10⁵

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  int magicalString(int n)
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Solution
```
public Solution()
```

Method Detail
- magicalString
```
public int magicalString(int n)
```