旋变串判断

问题
给定两个字符串，str1和str2判断str2是否是str1的旋变串。
旋变串定义

示例：
str1 = abcd str2 = acdb
return false;

思想：
分段来看是否护卫旋变串，dp表加上递归。Dp表存0，1，-1值相等为一，不等为-1.
分成俩种四段来比较，顺位的俩段，和逆位置俩段。

代码

public class Code03_ScrambleString {
    
	
	public static boolean isScramble0(String str1,String str2) {
    
		if((str1==null&&str2!=null)||(str1!=null&&str2==null)) {
    
			return false;
		}
		if(str1==null&&str2==null) {
    
			return true;
		}
		if(str1.length()!=str2.length()) {
    
			return false;
		}
		char[] s1 = str1.toCharArray();
		char[] s2 = str2.toCharArray();
		return process(s1,0,s1.length,s2,0,s2.length);
	}
	private static boolean process(char[] s1, int L1, int R1, char[] s2, int L2, int R2) {
    
		if(L1 == R1) {
    
			return s1[L1] == s2[L2];
		}
		for(int end = L1;end<R1;end++) {
    
			//正位比较
			boolean p1 = process(s1, L1, end, s2, L2, L2+end-L1)&&process(s1, end+1, R1, s2, L2+end-L1+1, R2);
			//逆位比较
			boolean p2 = process(s1, L1, end, s2, R2-(L2+end-L1)+1, R2)&&process(s1, end+1, R1, s2, L2,R2-(L2+end-L1));
			if(p1||p2) {
    
				return true;
			}
		}
		return false;
	}
	public static boolean isScramble1(String str1,String str2) {
    
		if((str1==null&&str2!=null)||(str1!=null&&str2==null)) {
    
			return false;
		}
		if(str1==null&&str2==null) {
    
			return true;
		}
		if(str1.length()!=str2.length()) {
    
			return false;
		}
		char[] s1 = str1.toCharArray();
		char[] s2 = str2.toCharArray();
		int N = s1.length;
		int[][][] dp = new int[N][N][N+1];
		return process1(s1,s2,0,0,N,dp);
	}
	public static boolean process1(char[] s1,char[] s2,int L1,int L2,int size,int[][][] dp) {
    
		if(dp[L1][L2][size]!=0) {
    
			return dp[L1][L2][size] == 1;
		}
		boolean ans = false;
		if(size == 1) {
    
			ans = s1[L1] == s2[L2];
		}
		for(int end = L1;end<size;end++) {
    
			if((process1(s1,s2, L1+end,L2+end,size-end,dp)&&process1(s1,s2,L1,L2,end,dp))||
					(process1(s1, s2, L1, L2+size-end, end, dp)&&process1(s1, s2, L1+end, L2, size-end, dp))) {
    
				ans = true;
				break;
			}
		}
		dp[L1][L2][size] = ans?1:-1;
		return ans;
	}
	public static void main(String[] args) {
    
		Scanner scanner = new Scanner(System.in);
		while(scanner.hasNext()) {
    
			String str1 = scanner.nextLine();
			String str2 = scanner.nextLine();
			boolean ans = isScramble1(str1, str2);
			System.out.println(ans);	
		}

	}

}