java 打印结果 a b c e f g h

java 打印结果 a b c e f g h

package test;

import java.util.ArrayList;
import java.util.HashMap;

public class Tests {
public static void prin(HashMap map, String str) {
System.out.println(str);
if (map.containsKey(str)) {
ArrayList list = (ArrayList) map.get(str);
prin2(map, list, true);
}
}

public static void prin2(HashMap map, ArrayList list, boolean b) {
for(int i=0;i System.out.print(list.get(i));
}
if(b)
System.out.println();
for(int i=0;i String str = (String) list.get(i);
if (map.containsKey(str)) {
ArrayList l = (ArrayList) map.get(str);
prin2(map, l, i==list.size()-1);
}
}

}

public static void main(String[] args) {
ArrayList list = new ArrayList();
HashMap map = new HashMap();
String father = "";
boolean equ = true;
list.add(new String[]{"c", "a"});
list.add(new String[]{"b", "a"});
list.add(new String[]{"f", "b"});
list.add(new String[]{"e", "b"});
list.add(new String[]{"g", "c"});
list.add(new String[]{"h", "c"});
// list.add(new String[]{"m", "h"});
// list.add(new String[]{"n", "h"});

for (int i = 0; i < list.size(); i++) {
String[] strs = (String[]) list.get(i);
ArrayList lis = null;
if (map.containsKey(strs[1])) {
lis = (ArrayList) map.get(strs[1]);
lis.add(strs[0]);
map.put(strs[1], lis);
} else {
lis = new ArrayList();
lis.add(strs[0]);
map.put(strs[1], lis);
}

for (int j = 0; j < list.size(); j++) {
String[] strss = (String[]) list.get(j);
if (strs[1].equals(strss[0])) equ = false;
}
if (equ) father = strs[1];
}
prin(map, father);
}
}
试试吧，不过位置肯定不能这样好看，需要你仔细的调试一下。 main方法注释了两行

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