网易开通了一个开源软件的镜像站点

public class Combination {
public static void main(String[] args) {
String str = "abc";
combination(str);
}

public static void combination(String str) {
char[] arr = str.toCharArray();
comCombination(arr, 0);
}

private static void comCombination(char[] arr, int index) {
if (index == arr.length - 1) {
for (int i = 0; i < arr.length; i++) {
System.out.printf("%c ", arr[i]);
}
System.out.println();
return;
}
comCombination(arr, index + 1);
for (int i = index + 1; i < arr.length; i++) {
arr[index] ^= arr[i];
arr[i] ^= arr[index];
arr[index] ^= arr[i];
comCombination(arr, index + 1);
arr[index] ^= arr[i];
arr[i] ^= arr[index];
arr[index] ^= arr[i];
}
}
}
OUTPUT:
a b c
a c b
b a c
b c a
c b a
c a b