add implementation of minimum product subset calculation

Author: Adityasinghvats

31Greedy/01_min_prod_subset.cpp

@@ -0,0 +1,40 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+int minProduct(vector<int>& v){
+    int cnt_negative = 0, cnt_zero = 0, cnt_pos = 0;
+    int prod_pos = 1, prod_neg = 1;
+    int largest_neg = INT_MIN;
+    for(const int ele: v){
+        if(ele<0) {
+            cnt_negative++;
+            prod_neg *= ele;
+            largest_neg = max(largest_neg, ele);
+        }
+        if(ele==0) cnt_zero++;
+        if(ele>0) {
+            cnt_pos++;
+            prod_pos *= ele;
+        }
+    }
+    //no negative exists
+    if(cnt_negative==0){
+        if(cnt_zero>0) return 0;
+        else {
+            auto it = min_element(v.begin(), v.end());
+            return *(it);
+        }
+    }else{//negatives exist
+        if(cnt_negative%2 == 0){//return products of all -ve except largest one
+            return (prod_neg / largest_neg) * prod_pos;
+        }else{
+            //product of all +ve and -ve
+            return prod_neg*prod_pos;
+        }
+    }
+}
+
+int main(){
+    vector<int> v {2, 3, 1, 4, 2, 0};
+    cout<<minProduct(v);
+}