Update solution.cpp

Author: suhas142

Heaps/Find the running medium/solution.cpp

@@ -1 +1,79 @@
+/*
+In this question we divide the already entered elements into 2 halves 
+the elements in the half with smaller elemenrs go into a max heap 
+the elememts in the half with bigger elemenrs go in min heap 
+If there are even no of elements we use biggest element of smaller half and
+smaller element of bigger half to compute the median
+In case of odd no of elements we keep 1 extra element in the max heap or min heap
+and use the heap with more elements to calculate median 
+*/
+#include<bits/stdc++.h>
+using namespace std;
 
+priority_queue<int, vector<int>, greater <int> > min_heap; //making a min heap 
+priority_queue<int> max_heap; //making a max heap
+
+int absh(int x){ //function to return absolute value of an int
+ if(x>0) return x;
+ else return (-1*x);
+}
+
+void add(int a) //function to add a number 
+{
+ if( max_heap.size() && a >= max_heap.top()) //if the number is bigger than the current median 
+ min_heap.push(a); //add in the min heap 
+ else
+ max_heap.push(a); // otherwise max heap 
+
+ if(absh(max_heap.size() - min_heap.size()) > 1) //if the difference between the number of elements 
+ { //larger than 1 adjust elements within the heaps to make it 0
+ if(max_heap.size() > min_heap.size()) //if max heap has more elements transfer one to min heap 
+ {
+ int temp = max_heap.top();
+ max_heap.pop();
+ min_heap.push(temp);
+ }
+ else //if min heap has more elements transfer it to max heap
+ {
+ int temp = min_heap.top();
+ min_heap.pop();
+ max_heap.push(temp);
+ }
+ }
+}
+
+double get_median() //function to return median with current elements 
+{
+ int total = min_heap.size() + max_heap.size();
+ double ret;
+ if(total%2 == 1) //check if the no of elements is odd, if it is odd we'll have a unique median 
+ {
+ if(max_heap.size() > min_heap.size()) //checking which of the 2 heaps has the median
+ ret = max_heap.top(); 
+ else
+ ret = min_heap.top();
+ }
+ else //if it is even we have to take the mean of 2 central elements 
+ {
+ ret = 0;
+ if(max_heap.empty() == false)
+ ret += max_heap.top(); //adding 1st central element 
+ if(min_heap.empty() == false)
+ ret += min_heap.top(); //adding 2nd central element 
+ ret/=2; // taking mean of both 
+ }
+ return ret;
+}
+
+int main()
+{
+ cout << setprecision(1) << fixed;
+ int n, a;
+ cin >> n;
+ for(int i = 1; i<=n; i++)
+ {
+ cin >> a;
+ add(a);
+ cout << get_median() << endl;
+ }
+}