Add 216_Combination_Sum_III.java

Author: Sean Prashad

Backtracking/216_Combination_Sum_III.java

@@ -0,0 +1,20 @@
+class Solution {
+ public List<List<Integer>> combinationSum3(int k, int n) {
+ List<List<Integer>> result = new ArrayList<>();
+ dfs(k, n, 1, new ArrayList<>(), result);
+ return result;
+ }
+
+ private void dfs(int k, int n, int idx, List<Integer> tempResult, List<List<Integer>> result) {
+ if (tempResult.size() == k && n == 0) {
+ result.add(new ArrayList<>(tempResult));
+ return;
+ }
+
+ for (int i = idx; i <= 9; i++) {
+ tempResult.add(i);
+ dfs(k, n - i, i + 1, tempResult, result);
+ tempResult.remove(tempResult.size() - 1);
+ }
+ }
+}