Add priority_queue implimentation using CPP

prioritqueue/1prqueue.cpp

@@ -0,0 +1,100 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+class priorityqueue{
+    public:
+    vector<int>pq;
+
+    bool isempty(){
+        return pq.size()==0;
+    }
+    int getmin(){
+        if(isempty()){
+            return 0;
+        }
+        return pq[0];
+    }
+    int  getsize(){
+        return pq.size();
+    }
+    void insert(int x){
+        pq.push_back(x);
+        int child_index=pq.size()-1;
+        while(child_index>0){
+            int parent_index=(child_index-1)/2;
+
+            if(pq[child_index]<pq[parent_index]){
+                int temp=pq[child_index];
+                pq[child_index]=pq[parent_index];
+                pq[parent_index]=temp;
+            }
+            else{
+                break;
+            }
+            child_index=parent_index;
+        }   
+    }
+    int removemin(){
+        if(isempty()){
+            return 0;
+        }
+        int ans=pq[0];
+        pq[0]=pq[pq.size()-1];
+        pq.pop_back();
+
+        //downheapify
+        int parent_index=0;
+        int leftchild_index=2*parent_index+1;
+        int rightchild_index=2*parent_index+2;
+
+
+
+        while(leftchild_index<pq.size()){
+            int min_index=parent_index;
+
+
+            if(pq[min_index]>pq[leftchild_index]){
+                min_index=leftchild_index;
+            }
+            if(rightchild_index<pq.size() && pq[rightchild_index]<pq[min_index]){
+                min_index=rightchild_index;
+            }
+
+
+
+
+
+            int temp=pq[min_index];
+            pq[min_index]=pq[parent_index];
+            pq[parent_index]=temp;
+            parent_index=min_index;
+            int leftchild_index=2*parent_index+1;
+            int rightchild_index=2*parent_index+2;
+            if(min_index==parent_index){
+                break;
+            }
+
+        }
+        return ans;
+    }
+
+};
+int main(){
+    priorityqueue p;
+    p.insert(100);
+    p.insert(10);
+    p.insert(15);
+    p.insert(4);
+    p.insert(17);
+    p.insert(21);
+    p.insert(67);
+    cout<<p.getsize()<<endl;
+    while(!p.isempty()){
+        cout<<p.removemin()<<" ";
+    }
+    cout<<endl;
+
+
+
+
+}

prioritqueue/stlpriorityqueue.cpp

@@ -0,0 +1,38 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+//max priority queue , mapheap 
+// int main(){
+//     priority_queue<int>pq;
+//     pq.push(78);
+//     pq.push(8);
+//     pq.push(128);
+//     pq.push(71);
+//     pq.push(9);
+//     pq.push(14);
+//     cout<<pq.size()<<endl;
+//     while(!pq.empty()){
+//         cout<<pq.top()<<"   ";
+//         pq.pop();
+//     }
+// }
+
+
+
+
+//minheap queue , minheap
+
+int main(){
+    priority_queue<int,vector<int>,greater<int>>pq;
+    pq.push(78);
+    pq.push(8);
+    pq.push(128);
+    pq.push(71);
+    pq.push(9);
+    pq.push(14);
+    cout<<pq.size()<<endl;
+    while(!pq.empty()){
+        cout<<pq.top()<<"   ";
+        pq.pop();
+    }
+}