Question

How to check if the sum of two halves of a number is equal in JavaScript

Answer 1

function halvesSumEqual(n) {
  const s = Math.abs(n).toString();

  if (s.length % 2 !== 0) return false;

  const half = s.length / 2;

  const leftSum  = [...s.slice(0, half)].reduce((a, c) => a + Number(c), 0);
  const rightSum = [...s.slice(half)].reduce((a, c) => a + Number(c), 0);

  return leftSum === rightSum;
}


function main() {
    const testNumbers = [1212, 123123, 45454545, 123, 1213];

    for (const n of testNumbers) {
        console.log(`${n} -> ${halvesEqual(n) ? "equal halves" : "not equal"}`);
    }
}

main();



/*
run:

1212 -> equal halves
123123 -> equal halves
45454545 -> equal halves
123 -> not equal
1213 -> not equal

*/

 

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