alphametic puzzle solver (brute force)

alphametic_solver.js

// alphametic puzzle solver (brute force)

const solve = (a, b, c, s) => {
  const uniq = [...new Set([...(a+b+c+s)])];
  const res = [];
  const rec = nums => {
    if (nums.length >= uniq.length) {
      const an = +[...a].map(l => nums[uniq.indexOf(l)]).join``;
      const bn = +[...b].map(l => nums[uniq.indexOf(l)]).join``;
      const cn = +[...c].map(l => nums[uniq.indexOf(l)]).join``;
      const sn = +[...s].map(l => nums[uniq.indexOf(l)]).join``;
      if (an + bn +cn === sn) {
        res.push(nums);
      }
      return;
    }
    for (let i = 0; i < 10; ++i) {
      if (!nums.includes(i)) {
        rec([...nums, i]);
      }
    }
  };
  rec([]);
  
  res.map(nums => {
    const an = +[...a].map(l => nums[uniq.indexOf(l)]).join``;
    const bn = +[...b].map(l => nums[uniq.indexOf(l)]).join``;
    const cn = +[...c].map(l => nums[uniq.indexOf(l)]).join``;
    const sn = +[...s].map(l => nums[uniq.indexOf(l)]).join``;
    console.log(`${an} + ${bn} + ${cn} = ${sn}`);
  });
};

solve('aaa', 'bbb', 'ccc', 'baac');
solve('', 'send', 'more', 'money');