Add 377_Combination_Sum_IV.java

Author: Sean Prashad

Dynamic Programming/377_Combination_Sum_IV.java

@@ -0,0 +1,30 @@
+class Solution {
+    public int combinationSum4(int[] nums, int target) {
+        int[] dp = new int[target + 1];
+        Arrays.fill(dp, -1);
+        dp[0] = 1;
+
+        return helper(nums, target, dp);
+    }
+
+    private int helper(int[] nums, int remainder, int[] dp) {
+        if (remainder < 0) {
+            return 0;
+        }
+        if (remainder == 0) {
+            return 1;
+        }
+
+        if (dp[remainder] != -1) {
+            return dp[remainder];
+        }
+
+        int result = 0;
+        for (int i = 0; i < nums.length; i++) {
+            result += helper(nums, remainder - nums[i], dp);
+        }
+
+        dp[remainder] = result;
+        return result;
+    }
+}