Given 2 input stacks with elements in an unsorted manner. Problem is to merge them into a new final stack, such that the elements become arranged in a sorted manner.
Examples:
Input : s1 : 9 4 2 1
s2: 8 17 3 10
Output : final stack: 1 2 3 4 8 9 10 17
Input : s1 : 5 7 2 6 4
s2 : 12 9 3
Output : final stack: 2 3 4 5 6 7 9 12
Create an empty stack to store result. We first insert elements of both stacks into the result. Then we sort the result stack.
C++
// C++ program to merge to unsorted stacks // into a third stack in sorted way. #include <bits/stdc++.h> using namespace std;
// Sorts input stack and returns sorted stack. stack<int> sortStack(stack<int>& input)
{ stack<int> tmpStack;
while (!input.empty()) {
// pop out the first element
int tmp = input.top();
input.pop();
// while temporary stack is not empty and top
// of stack is greater than temp
while (!tmpStack.empty() && tmpStack.top() > tmp) {
// pop from temporary stack and push
// it to the input stack
input.push(tmpStack.top());
tmpStack.pop();
}
// push temp in tempory of stack
tmpStack.push(tmp);
}
return tmpStack;
} stack<int> sortedMerge(stack<int>& s1, stack<int>& s2)
{ // Push contents of both stacks in result
stack<int> res;
while (!s1.empty()) {
res.push(s1.top());
s1.pop();
}
while (!s2.empty()) {
res.push(s2.top());
s2.pop();
}
// Sort the result stack.
return sortStack(res);
} // main function int main()
{ stack<int> s1, s2;
s1.push(34);
s1.push(3);
s1.push(31);
s2.push(1);
s2.push(12);
s2.push(23);
// This is the temporary stack
stack<int> tmpStack = sortedMerge(s1, s2);
cout << "Sorted and merged stack :\n";
while (!tmpStack.empty()) {
cout << tmpStack.top() << " ";
tmpStack.pop();
}
} |
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Java
// Java program to merge to unsorted stacks // into a third stack in sorted way. import java.io.*;
import java.util.*;
public class GFG {
// This is the temporary stack
static Stack<Integer> res = new Stack<Integer>();
static Stack<Integer> tmpStack = new Stack<Integer>();
// Sorts input stack and returns
// sorted stack.
static void sortStack(Stack<Integer> input)
{
while (input.size() != 0)
{
// pop out the first element
int tmp = input.peek();
input.pop();
// while temporary stack is not empty and
// top of stack is greater than temp
while (tmpStack.size() != 0 &&
tmpStack.peek() > tmp)
{
// pop from temporary stack and push
// it to the input stack
input.push(tmpStack.peek());
tmpStack.pop();
}
// push temp in tempory of stack
tmpStack.push(tmp);
}
}
static void sortedMerge(Stack<Integer> s1,
Stack<Integer> s2)
{
// Push contents of both stacks in result
while (s1.size() != 0) {
res.push(s1.peek());
s1.pop();
}
while (s2.size() != 0) {
res.push(s2.peek());
s2.pop();
}
// Sort the result stack.
sortStack(res);
}
// main function
public static void main(String args[])
{
Stack<Integer> s1 = new Stack<Integer>();
Stack<Integer> s2 = new Stack<Integer>();
s1.push(34);
s1.push(3);
s1.push(31);
s2.push(1);
s2.push(12);
s2.push(23);
sortedMerge(s1, s2);
System.out.println("Sorted and merged stack :");
while (tmpStack.size() != 0) {
System.out.print(tmpStack.peek() + " ");
tmpStack.pop();
}
}
} // This code is contributed by Manish Shaw // (manishshaw1) |
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C#
// C# program to merge to unsorted stacks // into a third stack in sorted way. using System;
using System.Collections.Generic;
class GFG {
// Sorts input stack and returns
// sorted stack.
static Stack<int> sortStack(ref Stack<int> input)
{
Stack<int> tmpStack = new Stack<int>();
while (input.Count != 0)
{
// pop out the first element
int tmp = input.Peek();
input.Pop();
// while temporary stack is not empty and
// top of stack is greater than temp
while (tmpStack.Count != 0 &&
tmpStack.Peek() > tmp)
{
// pop from temporary stack and push
// it to the input stack
input.Push(tmpStack.Peek());
tmpStack.Pop();
}
// push temp in tempory of stack
tmpStack.Push(tmp);
}
return tmpStack;
}
static Stack<int> sortedMerge(ref Stack<int> s1,
ref Stack<int> s2)
{
// Push contents of both stacks in result
Stack<int> res = new Stack<int>();
while (s1.Count!=0) {
res.Push(s1.Peek());
s1.Pop();
}
while (s2.Count!=0) {
res.Push(s2.Peek());
s2.Pop();
}
// Sort the result stack.
return sortStack(ref res);
}
// main function
static void Main()
{
Stack<int> s1 = new Stack<int>();
Stack<int> s2 = new Stack<int>();
s1.Push(34);
s1.Push(3);
s1.Push(31);
s2.Push(1);
s2.Push(12);
s2.Push(23);
// This is the temporary stack
Stack<int> tmpStack = new Stack<int>();
tmpStack = sortedMerge(ref s1,ref s2);
Console.Write("Sorted and merged stack :\n");
while (tmpStack.Count!=0) {
Console.Write(tmpStack.Peek() + " ");
tmpStack.Pop();
}
}
} // This code is contributed by Manish Shaw // (manishshaw1) |
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Output:
Sorted and merged stack : 34 31 23 12 3 1
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Improved By : manishshaw1