01-2.js

function main() {
  function findFirstDuplicateFrequency(input) {
    const inputFrequencies = input
      .replace(/, /g, '\n')
      .split('\n')
      .map(change => parseInt(change, 10));
    const seenFrequencies = new Set([0]);
    let frequency = 0;

    while (true) {
      for (let change of inputFrequencies) {
        frequency += change;
        if (seenFrequencies.has(frequency)) {
          return frequency;
        }
        seenFrequencies.add(frequency);
      }
    }
  }

  console.clear();
  console.log('Test (+1, -1):', findFirstDuplicateFrequency('+1, -1') === 0);
  console.log(
    'Test (+3, +3, +4, -2, -4):',
    findFirstDuplicateFrequency('+3, +3, +4, -2, -4') === 10
  );
  console.log(
    'Test (-6, +3, +8, +5, -6):',
    findFirstDuplicateFrequency('-6, +3, +8, +5, -6') === 5
  );
  console.log(
    'Test (+7, +7, -2, -7, -4):',
    findFirstDuplicateFrequency('+7, +7, -2, -7, -4') === 14
  );
  console.log('Result:', findFirstDuplicateFrequency(givenInput));
}

const givenInput = `
-2
-3
+4
-15
-15
+18
-7
+11
-16
-14
+2
-6
+16
+6
+14
-15
+12
-5
+17
-10
-20
-19
-14
-10
+4
-11
+10
-1
+12
-17
-2
+1
-17
+9
+4
+19
+11
-17
+15
-12
+5
+4
-1
-10
-19
-16
-9
+18
+2
+4
-19
+16
+6
-16
-14
+7
-9
+7
+17
+17
-14
+6
-22
-13
-2
-1
-18
-3
+19
+19
+16
-22
+14
-2
-3
+2
-18
-15
-14
-4
-15
+1
-3
-8
+18
-11
+6
-7
+17
+7
-8
-13
-4
+7
-15
-11
+7
+9
-7
+1
-20
-19
-18
-17
-12
+7
-16
-11
-4
-8
-4
-3
-2
+3
-15
+18
+5
+14
+15
+2
-19
+5
-13
+19
+9
+8
+5
-1
-19
+11
+2
+13
-17
+9
-16
+14
+20
+12
+8
+10
+17
-15
-8
+15
+19
-14
-3
-10
+2
+4
-1
+14
-12
+15
-2
-11
-14
-18
+6
-12
+7
+18
+15
+6
+12
+3
-6
+17
+11
+14
+13
+3
+6
-11
-19
-5
+14
-10
-7
+18
-8
-13
-2
+19
-18
-17
+11
+14
+17
+1
+26
+6
+15
+21
-5
+12
+6
+4
+10
-8
+16
-14
+4
-1
+17
-15
-23
+15
+18
+19
+10
-18
-2
+15
+15
+13
+5
+10
-8
+2
-18
+13
+15
+8
-19
+2
-4
-3
+20
-3
+12
+6
+13
+13
-15
+6
-15
+3
+7
-19
+11
+17
+15
-4
-10
-14
-20
+18
-11
-17
+8
+12
+3
-11
+7
-13
-4
+19
-7
-17
+12
+9
+13
+7
-13
+24
-2
+14
-5
+10
-6
-1
-8
-5
-6
+5
+12
+16
+5
-14
+19
+18
-9
-6
-12
-2
+19
-12
-9
+5
-4
-9
-9
+16
-19
-14
-7
-24
-20
+16
+12
+19
+20
-15
+26
+21
-2
+12
+4
-2
+18
-17
-12
-20
+2
+9
+14
+16
+12
-9
+14
+17
-19
+11
+3
-13
-3
+11
-14
+18
+9
-16
-2
+19
+7
-10
-3
+4
+10
+15
+19
-2
-5
+2
+2
-11
+6
-17
-11
+6
-10
+16
+7
-1
-2
+19
+6
+16
-12
+14
-5
+19
-12
+1
-6
-6
-2
+7
+19
+17
-4
+3
+3
+17
+16
-2
-10
-1
-14
-2
-17
-11
+3
-21
+15
+11
+7
-3
-18
+1
-15
-11
+1
-18
+11
+15
-17
-16
-19
+9
-5
+16
-18
+13
+16
-17
-1
-3
-2
+20
+14
-13
-17
+13
+5
+2
+19
+22
-3
-22
+10
-13
+2
-29
-27
-16
+17
-27
+18
-13
-4
+6
-5
+12
-16
-9
+3
+1
+10
-25
-1
-19
+13
+12
+2
-6
-12
+3
+25
+28
-4
+2
+17
-9
+63
+23
-8
+9
-6
+15
-14
+12
+6
+18
-6
-15
+12
-16
-3
+15
+24
+19
-6
+4
-8
-19
+4
+4
-20
-1
+24
+10
-9
+13
+11
+2
+11
+14
-2
+18
-12
+1
-17
+6
+1
-16
+10
+4
+9
-6
+10
-14
-2
+22
+2
+6
+10
-19
-24
+10
+11
+14
+2
+5
+18
+29
+1
+20
+7
+3
-12
+25
-21
+24
+4
-18
+1
+51
+19
-17
-23
+31
-15
+27
+2
+19
-16
+1
+18
+9
+22
+6
+15
-19
+14
-7
+3
+14
-7
-15
+18
-8
-1
-14
-7
-16
+22
+22
-2
+18
+2
-15
-39
+5
+21
-5
-2
+4
+1
+9
-58
+6
-95
-85
-5
+1
+7
+9
+15
-117
-12
-14
-18
+70
+9
-17
+93
-37
-134
-90
+22
-19
-7
-59
+14
-13
-47
+213
+81022
+9
+5
+4
-3
-16
-2
+4
+2
+5
-12
-9
-13
+2
-18
-18
-14
+7
+18
-19
+13
-1
-6
+9
-1
-18
+15
-14
-4
+12
-1
+5
+16
-7
+12
+6
-16
+13
+10
+3
-11
-13
+6
-7
+16
+3
-6
+19
-15
+14
-1
+19
+19
+13
-9
-3
-10
-14
+15
-9
+19
-6
+10
-7
+11
-1
+3
+2
-3
+8
+3
+13
+6
+3
+2
+18
+9
-17
+13
+15
-13
+9
+2
+19
+14
-13
+8
+18
+6
-4
-18
+1
-19
-1
+10
-5
-11
-10
-16
-4
-5
+3
-13
-19
-18
+16
+16
-5
+16
-10
-8
+9
+14
+1
+9
-3
+19
-12
+11
+12
+5
+19
-9
+4
+15
+19
-4
-10
-12
-18
-16
+13
-4
-16
-14
-15
+18
+1
-8
-7
-18
+3
-21
+9
-7
+8
+18
+2
-11
+6
+10
+9
+11
-21
+19
+4
+2
+7
+10
-16
+13
+9
+9
+16
+9
+13
-11
+16
+10
+14
+13
-5
-10
-16
-2
-2
+6
+19
+1
-16
+14
-13
+3
-5
-4
+12
-5
+22
+11
-5
+13
+4
+13
+19
+18
-13
+15
+19
-12
-11
-19
-12
+5
-19
+18
-19
+5
-13
-10
+15
-8
-2
-2
-11
-6
+5
-4
+21
+18
-5
+18
-11
+19
+12
-5
+4
-16
-10
+11
-16
+13
+11
-1
+15
+4
+13
-15
+14
-7
+19
+10
-8
+19
+4
-7
+19
+8
+14
-7
+3
+13
+19
-9
+4
-17
-19
-11
-11
-4
-16
-21
-5
+1
+16
-11
-15
-18
-13
-7
-13
-21
-18
+10
+14
+13
-7
-1
-4
+17
+20
+12
-24
+3
-8
+3
+10
+11
+11
-16
+13
+12
+19
-2
+7
+6
+5
+3
+10
+15
+2
+11
+14
-9
-1
-19
-16
+9
+17
-13
+4
+6
+2
+13
+16
+19
+12
+1
+18
+17
+19
+5
-8
+6
+10
+16
-9
+13
-8
-9
+5
-12
-7
-16
+4
-12
+18
-19
-7
+2
+2
-19
+10
+19
+9
-6
-18
+4
+18
-11
-13
-11
-16
+3
-4
-11
-2
+10
-14
+16
+14
-1
+2
+1
+4
-9
+17
-5
-14
-15
-13
+16
-8
-11
+2
+19
+23
+15
-13
+20
+3
+7
+9
+17
+10
-11
-19
-19
+9
-17
+12
-20
-22
+16
-9
-18
-10
-9
-81046
`.trim();

main();