[LeetCode] Scramble String

 1 class Solution {
 2 public:
 3     bool isScramble(string s1, string s2) {
 4         if (s1 == s2) return true;
 5         int n = s1.length();
 6         int counts[26] = {0};
 7         for (int i = 0; i < n; i++) {
 8             counts[s1[i] - 'a']++;
 9             counts[s2[i] - 'a']--;
10         }
11         for (int i = 0; i < 26; i++)
12             if (counts[i]) return false;
13         for (int i = 1; i < n; i++) {
14             if (isScramble(s1.substr(0, i), s2.substr(0, i)) && isScramble(s1.substr(i), s2.substr(i)))
15                 return true;
16             if (isScramble(s1.substr(0, i), s2.substr(n - i)) && isScramble(s1.substr(i), s2.substr(0, n - i)))
17                 return true;
18         }
19         return false;
20     }
21 };