Given a stack of integers S and an array of integers arr[], the task is to check if all the array elements are present in the stack or not.
Examples:
Input: S = {10, 20, 30, 40, 50}, arr[] = {20, 30}
Output: Yes
Explanation:
Elements 20 and 30 are present in the stack.Input: S = {50, 60}, arr[] = {60, 50}
Output: Yes
Explanation:
Elements 50 and 60 are present in the stack.
Approach: The idea is to maintain the frequency of array elements in a Hashmap. Now, while the stack is not empty, keep popping the elements out from the stack and reduce the frequency of elements from the Hashmap. Finally, when the stack is empty, check that the frequency of every element in the hash-map is zero or not. If found to be true, print Yes. Otherwise, print No.
Below is the implementation of the above approach:
C++
// C++ program of the above approach #include<bits/stdc++.h> using namespace std; // Function to check if all array // elements is present in the stack bool checkArrInStack(stack< int >s, int arr[], int n) { map< int , int >freq; // Store the frequency // of array elements for ( int i = 0; i < n; i++) freq[arr[i]]++; // Loop while the elements in the // stack is not empty while (!s.empty()) { int poppedEle = s.top(); s.pop(); // Condition to check if the // element is present in the stack if (freq[poppedEle]) freq[poppedEle] -= 1; } if (freq.size() == 0) return 0; return 1; } // Driver code int main() { stack< int >s; s.push(10); s.push(20); s.push(30); s.push(40); s.push(50); int arr[] = {20, 30}; int n = sizeof arr / sizeof arr[0]; if (checkArrInStack(s, arr, n)) cout << "YES\n" ; else cout << "NO\n" ; } // This code is contributed by Stream_Cipher |
Java
// Java program of // the above approach import java.util.*; class GFG{ // Function to check if all array // elements is present in the stack static boolean checkArrInStack(Stack<Integer>s, int arr[], int n) { HashMap<Integer, Integer>freq = new HashMap<Integer, Integer>(); // Store the frequency // of array elements for ( int i = 0 ; i < n; i++) if (freq.containsKey(arr[i])) freq.put(arr[i], freq.get(arr[i]) + 1 ); else freq.put(arr[i], 1 ); // Loop while the elements in the // stack is not empty while (!s.isEmpty()) { int poppedEle = s.peek(); s.pop(); // Condition to check if the // element is present in the stack if (freq.containsKey(poppedEle)) freq.put(poppedEle, freq.get(poppedEle) - 1 ); } if (freq.size() == 0 ) return false ; return true ; } // Driver code public static void main(String[] args) { Stack<Integer> s = new Stack<Integer>(); s.add( 10 ); s.add( 20 ); s.add( 30 ); s.add( 40 ); s.add( 50 ); int arr[] = { 20 , 30 }; int n = arr.length; if (checkArrInStack(s, arr, n)) System.out.print( "YES\n" ); else System.out.print( "NO\n" ); } } // This code is contributed by 29AjayKumar |
Python3
# Python program of # the above approach # Function to check if all array # elements is present in the stack def checkArrInStack(s, arr): freq = {} # Store the frequency # of array elements for ele in arr: freq[ele] = freq.get(ele, 0 ) + 1 # Loop while the elements in the # stack is not empty while s: poppedEle = s.pop() # Condition to check if the # element is present in the stack if poppedEle in freq: freq[poppedEle] - = 1 if not freq[poppedEle]: del freq[poppedEle] if not freq: return True return False # Driver Code if __name__ = = "__main__" : s = [ 10 , 20 , 30 , 40 , 50 ] arr = [ 20 , 30 ] if checkArrInStack(s, arr): print ( "YES" ) else : print ( "NO" ) |
C#
// C# program of // the above approach using System; using System.Collections.Generic; class GFG{ // Function to check if all array // elements is present in the stack static bool checkArrInStack(Stack< int >s, int []arr, int n) { Dictionary< int , int >freq = new Dictionary< int , int >(); // Store the frequency // of array elements for ( int i = 0; i < n; i++) if (freq.ContainsKey(arr[i])) freq[arr[i]] = freq[arr[i]] + 1; else freq.Add(arr[i], 1); // Loop while the elements in the // stack is not empty while (s.Count != 0) { int poppedEle = s.Peek(); s.Pop(); // Condition to check if the // element is present in the stack if (freq.ContainsKey(poppedEle)) freq[poppedEle] = freq[poppedEle] - 1; } if (freq.Count == 0) return false ; return true ; } // Driver code public static void Main(String[] args) { Stack< int > s = new Stack< int >(); s.Push(10); s.Push(20); s.Push(30); s.Push(40); s.Push(50); int []arr = {20, 30}; int n = arr.Length; if (checkArrInStack(s, arr, n)) Console.Write( "YES\n" ); else Console.Write( "NO\n" ); } } // This code is contributed by 29AjayKumar |
Javascript
<script> // JavaScript program of the above approach // Function to check if all array // elements is present in the stack function checkArrInStack(s, arr, n) { var freq = new Map(); // Store the frequency // of array elements for ( var i = 0; i < n; i++) { if (freq.has(arr[i])) freq.set(arr[i], freq.get(arr[i])+1) else freq.set(arr[i], 1) } // Loop while the elements in the // stack is not empty while (s.length!=0) { var poppedEle = s[s.length-1]; s.pop(); // Condition to check if the // element is present in the stack if (freq.has(poppedEle)) freq.set(poppedEle, freq.get(poppedEle)-1); } if (freq.size == 0) return 0; return 1; } // Driver code var s = []; s.push(10); s.push(20); s.push(30); s.push(40); s.push(50); var arr = [20, 30]; var n = arr.length; if (checkArrInStack(s, arr, n)) document.write( "YES" ); else document.write( "NO" ); </script> |
YES
Time Complexity: O(N)
Auxiliary Space: O(N)
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