思路:原来以为题目值允许中分,后来才发现可以随意拆分,那么按照拆分距离,比较的数组可以分为前半段与原字符串前半段对应,后半段与原字符串后半段对应,或者颠倒,但是要保证程度相同,然后递归求解。使用动态规划防止超时。
public class Solution {
Map<String,Boolean> map=new HashMap<String, Boolean>();
public boolean isScramble(String s1, String s2) {
if (map.get(s1+","+s2)!=null) {
return map.get(s1+","+s2);
}
int length=s1.length();
if (length!=s2.length()) {
map.put(s1+","+s2, false);
return false;
}
boolean flag=false;
if (length==1) {
flag=s1.equals(s2);
map.put(s1+","+s2, flag);
return flag;
}
for (int i = 1; i <length&&!flag; i++) {
String s1b=s1.substring(0,i);
String s1e=s1.substring(i,length);
String s2b=s2.substring(0,i);
String s2e=s2.substring(i,length);
String ns2b=s2.substring(0,length-i);
String ns2e=s2.substring(length-i,length);
flag=(isScramble(s1b,s2b)&&isScramble(s1e,s2e))||(isScramble(s1b,ns2e)&&isScramble(s1e,ns2b));
}
map.put(s1+","+s2, flag);
return flag;
}
}