Check if an array contains all elements of a given range
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14 Sep, 2023
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An array containing positive elements is given. ‘A’ and ‘B’ are two numbers defining a range. Write a function to check if the array contains all elements in the given range.
Examples :
Input : arr[] = {1 4 5 2 7 8 3}
A : 2, B : 5
Output : Yes
Input : arr[] = {1 4 5 2 7 8 3}
A : 2, B : 6
Output : No
Method 1 : (Intuitive)
- The most intuitive approach is to sort the array and check from the element greater than ‘A’ to the element less than ‘B’. If these elements are in continuous order, all elements in the range exists in the array.
Algorithm
1. Check if A > B. If yes, return false as it is an invalid range.
2. Loop through each integer i in the range [A, B] (inclusive):
a. Initialize a boolean variable found to false.
b. Loop through each element j in the array arr:
i. If j is equal to i, set found to true and break out of the inner loop.
c. If found is still false after looping through all elements of arr, return false as i is not in the array.
3. If the loop completes without returning false, return true as all elements in the range [A, B] are found in arr.
Implementation of above approach
C++
#include <iostream> #include <algorithm> // for std::sort using namespace std; bool check_elements_in_range( int arr[], int n, int A, int B) { if (A > B) { return false ; // invalid range } for ( int i = A; i <= B; i++) { bool found = false ; for ( int j = 0; j < n; j++) { if (arr[j] == i) { found = true ; break ; } } if (!found) { return false ; // element not found in array } } return true ; // all elements in range found in array } int main() { int arr[] = {1, 4, 5, 2, 7, 8, 3}; int n = sizeof (arr) / sizeof (arr[0]); int A = 2, B = 5; if (check_elements_in_range(arr, n, A, B)) { cout << "Yes" << endl; } else { cout << "No" << endl; } return 0; } |
Java
public class Main { public static boolean checkElementsInRange( int [] arr, int A, int B) { if (A > B) { return false ; // invalid range } for ( int i = A; i <= B; i++) { boolean found = false ; for ( int j = 0 ; j < arr.length; j++) { if (arr[j] == i) { found = true ; break ; } } if (!found) { return false ; // element not found in array } } return true ; // all elements in range found in array } public static void main(String[] args) { int [] arr = { 1 , 4 , 5 , 2 , 7 , 8 , 3 }; int A = 2 , B = 5 ; if (checkElementsInRange(arr, A, B)) { System.out.println( "Yes" ); } else { System.out.println( "No" ); } } } |
Python
def check_elements_in_range(arr, n, A, B): if A > B: return False # invalid range for i in range (A, B + 1 ): found = False for j in range (n): if arr[j] = = i: found = True break if not found: return False # element not found in array return True # all elements in range found in array arr = [ 1 , 4 , 5 , 2 , 7 , 8 , 3 ] n = len (arr) A, B = 2 , 5 if check_elements_in_range(arr, n, A, B): print ( "Yes" ) else : print ( "No" ) |
C#
using System; namespace RangeCheckApp { class Program { static bool CheckElementsInRange( int [] arr, int A, int B) { if (A > B) { return false ; // invalid range } for ( int i = A; i <= B; i++) { bool found = false ; foreach ( int num in arr) { if (num == i) { found = true ; break ; } } if (!found) { return false ; // element not found in array } } return true ; // all elements in range found in array } static void Main( string [] args) { int [] arr = { 1, 4, 5, 2, 7, 8, 3 }; int A = 2, B = 5; if (CheckElementsInRange(arr, A, B)) { Console.WriteLine( "Yes" ); } else { Console.WriteLine( "No" ); } } } } |
Javascript
function checkElementsInRange(arr, A, B) { if (A > B) { return false ; // invalid range } for (let i = A; i <= B; i++) { let found = false ; for (let j = 0; j < arr.length; j++) { if (arr[j] === i) { found = true ; break ; } } if (!found) { return false ; // element not found in array } } return true ; // all elements in range found in array } const arr = [1, 4, 5, 2, 7, 8, 3]; const A = 2, B = 5; if (checkElementsInRange(arr, A, B)) { console.log( "Yes" ); } else { console.log( "No" ); } |
Output
Yes
Time complexity: O(n log n)
Auxiliary space: O(1)
Method 2 : (Hashing)
- We can maintain a count array or a hash table that stores the count of all numbers in the array that are in the range A…B. Then we can simply check if every number occurred at least once.
Algorithm:
- Initialize an empty unordered set.
- Insert all the elements of the array into the set.
- Traverse all the elements between A and B, inclusive, and check if each element is present in the set or not.
- If any element is not present in the set, return false.
- If all the elements are present in the set, return true.
C++
// C++ code for the following approach #include <bits/stdc++.h> using namespace std; // function that check all elements between A and B including // them are present in set or not bool check_elements( int arr[] , int n , int A, int B){ unordered_set< int >st; // put all the elements of array into set for ( int i=0 ;i<n ;i++){ st.insert(arr[i]); } // now check every between between A to B including them also, that they are // present in set or not for ( int i=A ;i<=B ; i++){ // element not present in set so return false // and no need to traverse further if (st.find(i) == st.end()){ return false ; } } // all elements between A and B including them are // present in set so return true return true ; } // Driver code int main() { // Defining Array and size int arr[] = { 1, 4, 5, 2, 7, 8, 3 }; int n = sizeof (arr) / sizeof (arr[0]); // A is lower limit and B is the upper limit // of range int A = 2, B = 5; // True denotes all elements were present if (check_elements(arr, n, A, B)) cout << "Yes" ; // False denotes any element was not present else cout << "No" ; return 0; } // this code is contributed by bhardwajji |
Java
// Java code for the following approach import java.util.*; class Main { // function that check all elements between A and B // including them are present in set or not public static boolean checkElements( int arr[], int n, int A, int B) { Set<Integer> st = new HashSet<Integer>(); // put all the elements of array into set for ( int i = 0 ; i < n; i++) { st.add(arr[i]); } // now check every between between A to B including // them also, that they are present in set or not for ( int i = A; i <= B; i++) { // element not present in set so return false // and no need to traverse further if (!st.contains(i)) { return false ; } } // all elements between A and B including them are // present in set so return true return true ; } // Driver code public static void main(String[] args) { // Defining Array and size int arr[] = { 1 , 4 , 5 , 2 , 7 , 8 , 3 }; int n = arr.length; // A is lower limit and B is the upper limit // of range int A = 2 , B = 5 ; // True denotes all elements were present if (checkElements(arr, n, A, B)) System.out.println( "Yes" ); // False denotes any element was not present else System.out.println( "No" ); } } |
Python3
# Python code for the following approach import collections # function that check all elements between A and B # including them are present in set or not def checkElements(arr, n, A, B): st = set () # put all the elements of array into set for i in range (n): st.add(arr[i]) # now check every between between A to B including # them also, that they are present in set or not for i in range (A, B + 1 ): # element not present in set so return false # and no need to traverse further if i not in st: return False # all elements between A and B including them are # present in set so return true return True # Driver code if __name__ = = "__main__" : # Defining Array and size arr = [ 1 , 4 , 5 , 2 , 7 , 8 , 3 ] n = len (arr) # A is lower limit and B is the upper limit # of range A = 2 B = 5 # True denotes all elements were present if checkElements(arr, n, A, B): print ( "Yes" ) # False denotes any element was not present else : print ( "No" ) |
C#
using System; using System.Collections.Generic; class MainClass { // function that check all elements between A and B // including them are present in set or not static bool CheckElements( int [] arr, int n, int A, int B) { HashSet< int > set = new HashSet< int >(); // put all the elements of array into set for ( int i = 0; i < n; i++) { set .Add(arr[i]); } // now check every between between A to B including // them also, that they are present in set or not for ( int i = A; i <= B; i++) { // element not present in set so return false // and no need to traverse further if (! set .Contains(i)) { return false ; } } // all elements between A and B including them are // present in set so return true return true ; } // Driver code public static void Main( string [] args) { // Defining Array and size int [] arr = { 1, 4, 5, 2, 7, 8, 3 }; int n = arr.Length; // A is lower limit and B is the upper limit // of range int A = 2, B = 5; // True denotes all elements were present if (CheckElements(arr, n, A, B)) Console.WriteLine( "Yes" ); // False denotes any element was not present else Console.WriteLine( "No" ); } } |
Javascript
// JavaScript code for the following approach // function that check all elements between A and B // including them are present in set or not function checkElements(arr, n, A, B) { let st = new Set(); // put all the elements of array into set for (let i = 0; i < n; i++) { st.add(arr[i]); } // now check every between between A to B including // them also, that they are present in set or not for (let i = A; i <= B; i++) { // element not present in set so return false // and no need to traverse further if (!st.has(i)) { return false ; } } // all elements between A and B including them are // present in set so return true return true ; } // Defining Array and size let arr = [1, 4, 5, 2, 7, 8, 3]; let n = arr.length; // A is lower limit and B is the upper limit of range let A = 2; let B = 5; // True denotes all elements were present if (checkElements(arr,n,A,B)) { console.log( "Yes" ); } // False denotes any element was not present else { console.log( "No" ); } |
Output
Yes
Time complexity : O(n logn)
Auxiliary space : O(max_element)
Method 3 : (Best):
Every element(x) in the range (A to B) has a corresponding unique index (x-A)
- Do a linear traversal of the array. If an element is found such that in the given range, i.e., |arr[i]| >= A and |arr[i]| <=B
- Negate the element at index (arr[i]-A) corresponding to this element arr[i].(do this only the element at that index is positive)
- Now, count the number of number of elements which are negative .This count must be equal to B-A+1.
- As, an element at an index is negative indicates that element corresponding to that index is present in array.
Implementation:
C++
#include <iostream> using namespace std; // Function to check the array for elements in // given range bool check_elements( int arr[], int n, int A, int B) { //Array should contain atleast B-A+1 elements if (n<B-A+1) return false ; // Range is the no. of elements that are // to be checked int range = B - A; // Traversing the array for ( int i = 0; i < n; i++) { // If an element is in range if ( abs (arr[i]) >= A && abs (arr[i]) <= B) { // Negating at index ‘element – A’ int z = abs (arr[i]) - A; if (arr[z] > 0) arr[z] = arr[z] * -1; } } // Checking whether elements in range 0-range // are negative int count = 0; for ( int i = 0; i <= range && i < n; i++) { // Element from range is missing from array if (arr[i] > 0) return false ; else count++; } if (count != (range + 1)) return false ; // All range elements are present return true ; } // Driver code int main() { // Defining Array and size int arr[] = { 1, 4, 5, 2, 7, 8, 3 }; int n = sizeof (arr) / sizeof (arr[0]); // A is lower limit and B is the upper limit // of range int A = 2, B = 5; // True denotes all elements were present if (check_elements(arr, n, A, B)) cout << "Yes" ; // False denotes any element was not present else cout << "No" ; return 0; } // This code is contributed by Sania Kumari Gupta |
C
#include <stdbool.h> #include <stdio.h> #include <stdlib.h> // Function to check the array for elements in // given range bool check_elements( int arr[], int n, int A, int B) { // Range is the no. of elements that are // to be checked int range = B - A; // Traversing the array for ( int i = 0; i < n; i++) { // If an element is in range if ( abs (arr[i]) >= A && abs (arr[i]) <= B) { // Negating at index ‘element – A’ int z = abs (arr[i]) - A; if (arr[z] > 0) arr[z] = arr[z] * -1; } } // Checking whether elements in range 0-range // are negative int count = 0; for ( int i = 0; i <= range && i < n; i++) { // Element from range is missing from array if (arr[i] > 0) return false ; else count++; } if (count != (range + 1)) return false ; // All range elements are present return true ; } // Driver code int main() { // Defining Array and size int arr[] = { 1, 4, 5, 2, 7, 8, 3 }; int n = sizeof (arr) / sizeof (arr[0]); // A is lower limit and B is the upper limit // of range int A = 2, B = 5; // True denotes all elements were present if (check_elements(arr, n, A, B)) printf ( "Yes" ); // False denotes any element was not present else printf ( "No" ); return 0; } // This code is contributed by Sania Kumari Gupta |
Java
// JAVA Code for Check if an array contains // all elements of a given range import java.util.*; class GFG { // Function to check the array for elements in // given range public static boolean check_elements( int arr[], int n, int A, int B) { // Range is the no. of elements that are // to be checked int range = B - A; // Traversing the array for ( int i = 0 ; i < n; i++) { // If an element is in range if (Math.abs(arr[i]) >= A && Math.abs(arr[i]) <= B) { int z = Math.abs(arr[i]) - A; if (arr[z] > 0 ) { arr[z] = arr[z] * - 1 ; } } } // Checking whether elements in range 0-range // are negative int count= 0 ; for ( int i = 0 ; i <= range && i<n; i++) { // Element from range is missing from array if (arr[i] > 0 ) return false ; else count++; } if (count!= (range+ 1 )) return false ; // All range elements are present return true ; } /* Driver program to test above function */ public static void main(String[] args) { // Defining Array and size int arr[] = { 1 , 4 , 5 , 2 , 7 , 8 , 3 }; int n = arr.length; // A is lower limit and B is the upper limit // of range int A = 2 , B = 5 ; // True denotes all elements were present if (check_elements(arr, n, A, B)) System.out.println( "Yes" ); // False denotes any element was not present else System.out.println( "No" ); } } // This code is contributed by Arnav Kr. Mandal. |
Python3
# Function to check the array for # elements in given range def check_elements(arr, n, A, B) : # Range is the no. of elements # that are to be checked rangeV = B - A # Traversing the array for i in range ( 0 , n): # If an element is in range if ( abs (arr[i]) > = A and abs (arr[i]) < = B) : # Negating at index ‘element – A’ z = abs (arr[i]) - A if (arr[z] > 0 ) : arr[z] = arr[z] * - 1 # Checking whether elements in # range 0-range are negative count = 0 for i in range ( 0 , rangeV + 1 ): if i > = n: break # Element from range is # missing from array if (arr[i] > 0 ): return False else : count = count + 1 if (count ! = (rangeV + 1 )): return False # All range elements are present return True # Driver code # Defining Array and size arr = [ 1 , 4 , 5 , 2 , 7 , 8 , 3 ] n = len (arr) # A is lower limit and B is # the upper limit of range A = 2 B = 5 # True denotes all elements # were present if (check_elements(arr, n, A, B)) : print ( "Yes" ) # False denotes any element # was not present else : print ( "No" ) # This code is contributed # by Yatin Gupta |
C#
// C# Code for Check if an array contains // all elements of a given range using System; class GFG { // Function to check the array for // elements in given range public static bool check_elements( int []arr, int n, int A, int B) { // Range is the no. of elements // that are to be checked int range = B - A; // Traversing the array for ( int i = 0; i < n; i++) { // If an element is in range if (Math.Abs(arr[i]) >= A && Math.Abs(arr[i]) <= B) { int z = Math.Abs(arr[i]) - A; if (arr[z] > 0) { arr[z] = arr[z] * - 1; } } } // Checking whether elements in // range 0-range are negative int count=0; for ( int i = 0; i <= range && i < n; i++) { // Element from range is // missing from array if (arr[i] > 0) return false ; else count++; } if (count != (range + 1)) return false ; // All range elements are present return true ; } // Driver Code public static void Main(String []args) { // Defining Array and size int []arr = {1, 4, 5, 2, 7, 8, 3}; int n = arr.Length; // A is lower limit and B is // the upper limit of range int A = 2, B = 5; // True denotes all elements were present if (check_elements(arr, n, A, B)) Console.WriteLine( "Yes" ); // False denotes any element was not present else Console.WriteLine( "No" ); } } // This code is contributed by vt_m. |
Javascript
<script> // Javascript Code for Check // if an array contains // all elements of a given range // Function to check the array for // elements in given range function check_elements(arr, n, A, B) { // Range is the no. of elements // that are to be checked let range = B - A; // Traversing the array for (let i = 0; i < n; i++) { // If an element is in range if (Math.abs(arr[i]) >= A && Math.abs(arr[i]) <= B) { let z = Math.abs(arr[i]) - A; if (arr[z] > 0) { arr[z] = arr[z] * - 1; } } } // Checking whether elements in // range 0-range are negative let count=0; for (let i = 0; i <= range && i < n; i++) { // Element from range is // missing from array if (arr[i] > 0) return false ; else count++; } if (count != (range + 1)) return false ; // All range elements are present return true ; } // Defining Array and size let arr = [1, 4, 5, 2, 7, 8, 3]; let n = arr.length; // A is lower limit and B is // the upper limit of range let A = 2, B = 5; // True denotes all elements were present if (check_elements(arr, n, A, B)) document.write( "Yes" ); // False denotes any element was not present else document.write( "No" ); </script> |
PHP
<?php // Function to check the // array for elements in // given range function check_elements( $arr , $n , $A , $B ) { // Range is the no. of // elements that are to // be checked $range = $B - $A ; // Traversing the array for ( $i = 0; $i < $n ; $i ++) { // If an element is in range if ( abs ( $arr [ $i ]) >= $A && abs ( $arr [ $i ]) <= $B ) { // Negating at index // ‘element – A’ $z = abs ( $arr [ $i ]) - $A ; if ( $arr [ $z ] > 0) { $arr [ $z ] = $arr [ $z ] * -1; } } } // Checking whether elements // in range 0-range are negative $count = 0; for ( $i = 0; $i <= $range && $i < $n ; $i ++) { // Element from range is // missing from array if ( $arr [ $i ] > 0) return -1; else $count ++; } if ( $count != ( $range + 1)) return -1; // All range elements // are present return true; } // Driver code // Defining Array and size $arr = array (1, 4, 5, 2, 7, 8, 3); $n = sizeof( $arr ); // A is lower limit and // B is the upper limit // of range $A = 2; $B = 5; // True denotes all // elements were present if ((check_elements( $arr , $n , $A , $B )) == true) echo "Yes" ; // False denotes any // element was not present else echo "No" ; // This code is contributed by aj_36 ?> |
Output
Yes
Time complexity : O(n)
Auxiliary space : O(1)