JavaScript: Find whether the members of a given array of integers is a permutation of numbers from 1 to a given integer

Last update on May 30 2022 10:02:23 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-123 with Solution

Write a JavaScript program to find whether the members of a given array of integers is a permutation of numbers from 1 to a given integer.

Pictorial Presentation:

JavaScript: Find whether the members of a given array of integers is a permutation of numbers from 1 to a given integer.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title> Find whether the members of a given array of integers is a permutation of numbers from 1 to a given integer</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function is_permutation(input_arr, n) {
    for (var i = 0; i < n; i++) {
        if (input_arr.indexOf(i + 1) < 0) 
          return false;
    }
    return true;
}
console.log(is_permutation([1, 2, 3, 4, 5], 5));
console.log(is_permutation([1, 2, 3, 5], 5));

Sample Output:

true
false

Flowchart:

ES6 Version:

function is_permutation(input_arr, n) {
    for (let i = 0; i < n; i++) {
        if (!input_arr.includes(i + 1)) 
          return false;
    }
    return true;
}
console.log(is_permutation([1, 2, 3, 4, 5], 5));
console.log(is_permutation([1, 2, 3, 5], 5));

Live Demo:

See the Pen javascript-basic-exercise-123 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to create the value of NOR of two given booleans.

JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04