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

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:

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

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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Previous: Write a JavaScript program to check whether a given array of integers represents either a strictly increasing or a strictly decreasing sequence.
Next: Write a JavaScript program to create the value of NOR of two given booleans.

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925

Output:

385
3025
2925