Finding the sum of all numbers in the nth row of an increasing triangle using JavaScript

JavascriptWeb DevelopmentFront End Technology

Increasing Triangle

For the purpose of this problem, suppose an increasing triangle to be like this −

   1
  2 3
 4 5 6
7 8 9 10

Problem

We are required to write a JavaScript function that takes in a number n and returns the sum of numbers present in the nth row of increasing triangle.

Example

Following is the code −

 Live Demo

const num = 15;
const rowSum = (num = 1) => {
   const arr = [];
   const fillarray = () => {
      let num = 0;
      for(let i = 1; i <= 10000; i++){
         const tempArr = [];
         for(let j = 0; j < i; j++){
            num++;
            tempArr.push(num)
         };
         arr.push(tempArr);
      };
   };
   fillarray()
   return arr[num-1].reduce((a, b)=>a + b, 0);
};
console.log(rowSum(num));

Output

1695
raja
Published on 19-Apr-2021 11:26:53
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