Create Combination Sum IV.java

Author: varunu28

Medium/Combination Sum IV.java

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+class Solution {
+  public int combinationSum4(int[] nums, int target) {
+    Integer[] dp = new Integer[target + 1];
+    return getCount(target, nums, dp);
+  }
+  
+  public int getCount(int target, int[] nums, Integer[] dp) {
+    if (dp[target] != null) {
+      return dp[target];
+    }
+    if (target == 0) {
+      return 1;
+    }
+    if (target < 0) {
+      return 0;
+    }
+    int total = 0;
+    for (int num : nums) {
+      if (target >= num) {
+        total += getCount(target - num, nums, dp);
+      }
+    }
+    return dp[target] = total;
+  }
+}