From 5cc1aabd9992c19bd7ce2f512add1e43baf6456f Mon Sep 17 00:00:00 2001
From: Harshil-1234 <101947443+Harshil-1234@users.noreply.github.com>
Date: Fri, 14 Oct 2022 12:01:15 +0530
Subject: [PATCH] N-queue problem by Love Babbar

---
 Stacks&Queues/N_queues.cpp | 98 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 Stacks&Queues/N_queues.cpp

diff --git a/Stacks&Queues/N_queues.cpp b/Stacks&Queues/N_queues.cpp
new file mode 100644
index 0000000..bd2f60a
--- /dev/null
+++ b/Stacks&Queues/N_queues.cpp
@@ -0,0 +1,98 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+class kQueue{
+
+    int n;
+    int k;
+    int*arr;
+    int *front;
+    int *rear;
+    int *next;
+    int freespot;
+
+    public:
+        kQueue(int n, int k){
+            this-> n = n;
+            this-> k = k;
+            front = new int[k];
+            rear = new int[k];
+
+            for(int i=0;i<k;i++){
+                front[i] = rear[i] = -1;
+            }
+
+            next = new int[n];
+
+            for(int i=0;i<n;i++){
+                next[i] = i+1;
+            }
+            next[n-1] = -1;
+
+            arr = new int[n];
+            freespot = 0;
+        }
+
+        void enqueue(int data, int qn){
+            // Step 1: Check for Overflow
+            if(freespot == -1){
+                cout<<"Queue Overflow"<<endl;
+                return;
+            }
+
+            //if can push, find first free index
+            int index = freespot;
+
+            //update freespot
+            freespot = next[index];
+
+            //check whether pushing first element in the kth queue:
+            if(front[qn-1] == -1){
+                front[qn-1] = index;
+            }else{
+                // link new element to the previous element
+                next[rear[qn-1]] = index;
+            }
+
+            next[index] = -1;
+
+            rear[qn-1] = index;
+
+            arr[index] = data;
+        }
+
+        int dequeue(int qn){
+            // Check if empty:
+            if(front[qn-1]==-1){
+                cout<<"Queue is empty"<<endl;
+                return -1;
+            }
+
+            // index to pop
+            int index = front[qn-1];
+
+            // front ko aage badhao
+            front[qn-1] = next[index];
+
+            // freespot ko manage
+            next[index] = freespot;
+            freespot = index;
+
+            return arr[index]; 
+        }
+
+};
+
+int main(){
+    kQueue q(10,3);
+    q.enqueue(10,1);
+    q.enqueue(15,1);
+    q.enqueue(20,2);
+    q.enqueue(25,1);
+
+    cout<<q.dequeue(1)<<endl;
+    cout<<q.dequeue(2)<<endl;
+    cout<<q.dequeue(1)<<endl;
+    cout<<q.dequeue(1)<<endl;
+    return 0;
+}
\ No newline at end of file