백준 9184 신나는 함수실행 javascript

문제

https://www.acmicpc.net/problem/9184

풀이

정의대로 코드 작성한 후 메모이제이션 한다.

코드

let fs = require('fs');
// let input = fs.readFileSync('/dev/stdin').toString().split('\n');
let input = fs.readFileSync('./b9184.txt').toString().split('\n');

let readlineIdx = 0;

const readInput = () => input[readlineIdx++];

const fillMax = 0;
let table = new Array(21);

function w(a, b, c) {
  if (a <= 0 || b <= 0 || c <= 0) {
    return 1;
  }

  if (a > 20 || b > 20 || c > 20) {
    return w(20, 20, 20);
  }

  if (table[a][b][c] !== fillMax) {
    return table[a][b][c];
  }

  if (a < b && b < c) {
    let t1 = table[a][b][c - 1] = w(a, b, c - 1);
    let t2 = table[a][b - 1][c - 1] = w(a, b - 1, c - 1);
    let t3 = table[a][b - 1][c] = w(a, b - 1, c);
    return table[a][b][c] = t1 + t2 - t3;
  }


  let t1 = table[a - 1][b][c] = w(a - 1, b, c);
  let t2 = table[a - 1][b - 1][c] = w(a - 1, b - 1, c);
  let t3 = table[a - 1][b][c - 1] = w(a - 1, b, c - 1);
  let t4 = table[a - 1][b - 1][c - 1] = w(a - 1, b - 1, c - 1);
  return table[a][b][c] = t1 + t2 + t3 - t4;

}

function main() {
  for (let i = 0; i < 21; ++i) {
    table[i] = new Array(21);
    for (let j = 0; j < 21; ++j) {
      table[i][j] = new Array(21).fill(fillMax);
    }
  }
  while (true) {
    let [a, b, c] = readInput().split(' ');
    a = Number(a);
    b = Number(b);
    c = Number(c);
    if (a === -1 && b === -1 && c === -1) break;
    console.log(`w(${a}, ${b}, ${c}) = ${w(a, b, c)}`);

  }
}

main();