BDCA 样例输出 ABCD 分析：二叉树中简单的知道“中序”和“后序”求“先序”的题，递归求解
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
String str1 = scanner.nextLine();
String str2 = scanner.nextLine();
showResult(str1, str2);
System.out.println();
}
}
private static void showResult(String str1, String str2) {
char chl = str2.charAt(str2.length() - 1);
System.out.print(chl);
int index = str1.indexOf(chl);
if (index > 0) {
showResult(str1.substring(0, index), str2.substring(0, index));
}
if (index < str1.length() - 1) {
showResult(str1.substring(index + 1), str2.substring(index, str2.length() - 1));
}
}
}