import java.util.ArrayList;

import java.util.List;

/**

* Author : WindAsMe

* File : combinationSum3.java

* Time : Create on 18-6-6

* Location : ../Home/JavaForLeeCode2/combinationSum3.java

* Function : LeeCode No.216

*/

public class combinationSum3 {

private static List<List<Integer>> ans = new ArrayList<>();

private static int[] paths = new int[100];

private static void robot(int index, int k, int n, int j) {

if (index >= k) {

List<Integer> temp = new ArrayList<>();

int sum = 0;

for(int i = 0; i < k; i++) {

sum += paths[i];

temp.add(paths[i]);

}

if (sum == n) {

ans.add(temp);

}

return;

}

for(int i = j; i <= 9; i++) {

paths[index] = i;

robot(index + 1, k, n, i+1);

}

}

private static List<List<Integer>> combinationSum3Result(int k, int n) {

ans.clear();

robot(0, k, n, 1);

return ans;

}

public static void main(String[] args) {

List<List<Integer>> lists = combinationSum3Result(3, 7);

for (List<Integer> list : lists) {

for (int j = 0; j < 3; j++) {

System.out.print(list.get(j) + " ");

}

System.out.println();

}

}

}