102_leetcode_Scramble String

Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.

Below is one possible representation of s1 = "great":

    great   /    \  gr    eat / \    /  \g   r  e   at           / \          a   t

To scramble the string, we may choose any non-leaf node and swap its two children.

For example, if we choose the node "gr" and swap its two children, it produces a scrambled string "rgeat".

    rgeat   /    \  rg    eat / \    /  \r   g  e   at           / \          a   t

We say that "rgeat" is a scrambled string of "great".

Similarly, if we continue to swap the children of nodes "eat" and "at", it produces a scrambled string "rgtae".

    rgtae   /    \  rg    tae / \    /  \r   g  ta  e       / \      t   a

We say that "rgtae" is a scrambled string of "great".

Given two strings s1 and s2 of the same length, determine if s2 is a scrambled string of s1

1:采用递归；2:注意递归结束条件；3:特殊情况进行处理；

    bool isScramble(string s1, string s2)    {        if(s1.size() != s2.size())        {            return false;        }        if(strcmp(s1.c_str(), s2.c_str()) == 0)        {            return true;        }                int A[256] = {0};        for(int i = 0; s1[i] != '\0' ; i++)        {            A[s1[i]]++;        }        for(int i = 0; s2[i] != '\0'; i++)        {            A[s2[i]]--;        }                for(int i = 0; i < 256; i++)        {            if(A[i] != 0)            {                return false;            }        }                bool flag = false;        int size = (int)s1.size();                for(int i = 1; i < size; i++)        {            flag = isScramble(s1.substr(0, i), s2.substr(0, i)) && isScramble(s1.substr(i, size - i), s2.substr(i, size - i));            if(flag == false)            {                flag = isScramble(s1.substr(0, i), s2.substr(size - i, i)) && isScramble(s1.substr(i, size - i), s2.substr(0, size - i));            }            if(flag)            {                break;            }        }        return flag;    }