Create: 0377-combination-sum-iv.cpp

cpp/0377-combination-sum-iv.cpp

@@ -0,0 +1,28 @@
+/*
+    Given an array of distinct integers nums and a target integer 'target', 
+    return the number of possible combinations that add up to target.
+
+    Ex. nums = [1,2,3] target = 4
+    Possible Combinations: (1,1,1,1) (1,1,2) (1,2,1) (1,3) (2,1,1,)
+    (2,2) (3,1). 
+    So, total number of combinations possible is 7.
+
+    Time: O(n * m)
+    Space: O(m)
+*/
+
+class Solution {
+public:
+    int combinationSum4(vector<int>& nums, int target) {
+    sort(nums.begin(), nums.end());
+    vector<unsigned int> dp(target+1, 0);
+    dp[0] = 1;
+    for(int total=1; total<=target; total++) {
+        for(int i=0; i<nums.size(); i++) {
+            if(nums[i] <= total) dp[total] += dp[total - nums[i]];
+            else break;
+        }
+    }
+    return dp[target];
+    }
+};