dp
sub[len][i][j] 表示s1从i开始与s2从j开始的长度为len是否为Scramble String
class Solution {
public:
bool sub[100][100][100];
bool isScramble(string s1, string s2) {
if(s1.length()!=s2.length())
return false;
int len = s1.length();
for(int i = 0;i<len;i++)
for(int j = 0;j<len;j++)
sub[1][i][j] = (s1[i]==s2[j])?1:0;
for(int k = 2;k<=len;k++)
for(int i = 0;i<=len- k ;i++)
for(int j = 0;j<=len-k;j++)
{
sub[k][i][j] = 0;
for(int p =i+1;p<i+k&&!sub[k][i][j];p++)
if( sub[p-i][i][j] && sub[k-p+i][p][p-i+j] ) //注意下标的变换
sub[k][i][j] =1;
else if( sub[p-i][i][k-p+i+j] &&sub[k-p+i][p][j])
sub[k][i][j]=1;
else
sub[k][i][j] = 0;
}
return sub[len][0][0];
}
};