Create subsetSumDP.cpp

Author: avidLearnerInProgress

subsetSumDP.cpp

@@ -0,0 +1,88 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+
+bool isSubSetSumRecursiveHelper(vector<int> v, int target, int n) {
+    if(n <= 0 || target < 0) return false;
+    if(target == 0) return true;
+    
+    bool include = isSubSetSumRecursiveHelper(v, target - v[n], n - 1);
+    bool exclude = isSubSetSumRecursiveHelper(v, target, n - 1);
+    return include || exclude;
+}
+
+
+bool isSubSetSumRecursive(vector<int> v, int target) {
+    if(v.size() == 0) return false;
+    
+    //pick last element or dont pick;
+    return isSubSetSumRecursiveHelper(v, target, v.size() - 1);
+    
+}
+
+
+
+unordered_map<string, int> mp;
+bool isSubsetSumMemoizedHelper(vector<int> v, int target, int n) {
+    
+    if(n <= 0 || target < 0) return false;
+    
+    if(target == 0) return true;
+    
+    string key = to_string(n) + '|' + to_string(target);
+    if(mp.find(key) == mp.end()) {
+        bool include = isSubsetSumMemoizedHelper(v, target - v[n], n - 1);
+        bool exclude = isSubsetSumMemoizedHelper(v, target, n - 1);
+        mp[key] = target;
+        
+        return include || exclude;
+    }
+    //else already found;
+    return mp[key];
+}
+
+
+bool isSubsetSumMemoized(vector<int> v, int target) {
+    if(v.size() == 0) return false;
+    return isSubsetSumMemoizedHelper(v, target, v.size() - 1);
+}
+
+
+bool isSubsetSumDP(vector<int> v, int target) {
+    if(v.size() == 0) return false;
+    
+    int n = v.size();
+    int dp[n + 1][target + 1];
+    
+    for(int i=0; i<=n; i++) {
+        dp[0][i] = false;
+    }
+    
+    for(int j=0; j<=target; j++) {
+        dp[j][0] = true;
+    }
+    
+    
+    for(int i=1; i<=n; i++) {
+        for(int j=1; j<=target; j++) {
+            
+            if(v[i-1] > j) {
+                dp[i][j] = dp[i-1][j];
+            }
+            else {
+                //include || exclude
+                dp[i][j] = dp[i-1][j] || dp[i-1][j - v[i-1]];
+            }
+        }
+    }
+    
+    return dp[n][target];
+}
+
+int main() {
+    cout<<isSubSetSumRecursive({1,2,3,4,5,6,7,8}, 7);
+    
+    cout<<isSubsetSumMemoized({1,2,3,4,5,6,7,8}, 7);
+    
+    cout<<isSubsetSumDP({1,2,3,4,5,6,7,8}, 7);
+}