Updated Readme

2 stacks in array.cpp

@@ -0,0 +1,116 @@
+/*Your task is to implement  2 stacks in one array efficiently .
+Input:
+The first line of the input contains an integer 'T' denoting the number of test cases. Then T test cases follow.
+First line of each test case contains an integer Q denoting the number of queries .
+A Query Q is of 4 Types
+(i)    1 1 x    (a query of this type means  pushing 'x' into the stack 1)
+(ii)   1 2      (a query of this type means to pop element from stack1  and print the poped element)
+(iii)  2 1 x  (a query of this type means pushing 'x' into the stack 2)
+(iv)  2 2     (a query of this type means to pop element from stack2 and print the poped element)
+The second line of each test case contains Q queries seperated by space.
+Output:
+The output for each test case will be space separated integers having -1 if the stack is empty else the element poped out from the stack.
+You are required to complete the 4  methods push1, push2 which takes one argument an integer 'x' to be pushed into the stack one and two  and pop1, pop2 which returns a integer poped out from stack one and two .
+Your Task:
+Since this is a function problem, you don't need to take any input. Just complete the provided functions.
+Constraints:
+1 <= T <= 100
+1 <= Q <= 100
+1 <= x <= 100
+Example:
+Input
+2
+6
+1 1 2 1 1 3 2 1 4 1 2 2 2 2 2
+4
+1 1 2 2 2 1 2 2 2
+Output
+3 4 -1
+-1 2 -1
+*/
+#include<bits/stdc++.h>
+
+using namespace std;
+
+class twoStacks
+{
+    int *arr;
+    int size;
+    int top1, top2;
+public:
+   twoStacks(int n=100){size = n; arr = new int[n]; top1 = -1; top2 = size;}
+
+   void push1(int x);
+   void push2(int x);
+   int pop1();
+   int pop2();
+};
+
+
+
+int main()
+{
+
+    int T;
+    cin>>T;
+    while(T--)
+    {
+        twoStacks *sq = new twoStacks();
+
+        int Q;
+        cin>>Q;
+        while(Q--){
+        int stack_no;
+        cin>>stack_no;
+        int QueryType=0;
+        cin>>QueryType;
+
+        if(QueryType==1)
+        {
+            int a;
+            cin>>a;
+            if(stack_no ==1)
+            sq->push1(a);
+            else if(stack_no==2)
+            sq->push2(a);
+        }else if(QueryType==2){
+        	if(stack_no==1)
+            cout<<sq->pop1()<<" ";
+            else if(stack_no==2)
+            cout<<sq->pop2()<<" ";
+
+        }
+        }
+        cout<<endl;
+    }
+}
+void twoStacks::push1(int x){
+    if(top1<top2-1){
+        top1++;
+        arr[top1]=x;
+    }
+}
+void twoStacks::push2(int x){
+    if(top1<top2-1){
+        top2--;
+        arr[top2]=x;
+    }
+}
+int twoStacks::pop1(){
+    if(top1>=0){
+        int x=arr[top1];
+        top1--;
+        return x;
+    }
+    else
+        return -1;
+}
+int twoStacks::pop2(){
+    if(top2<size){
+        int x=arr[top2];
+        top2++;
+        return x;
+    }
+    else
+        return -1;
+}

README.md

@@ -1 +1,3 @@
 README.md
+
+Added coding solutions for LCA, 2 stacks in an array and LRU cache.