const int L = 3;
const int I = 2;
const int O = 1;

const int K = 6;
const int D = 5;
const int U = 7;

const int N = 4;

var LOKI = int.Parse($"{L}{O}{K}{I}");
var IDUN = int.Parse($"{I}{D}{U}{N}");
var ODIN = int.Parse($"{O}{D}{I}{N}");
var THOR = LOKI + IDUN + IDUN;

Console.WriteLine($"LOKI + IDUN + ODIN = THOR");
Console.WriteLine($"{LOKI} + {IDUN} + {ODIN} = {THOR}");

LOKI + IDUN + ODIN = THOR
3162 + 2574 + 1524 = 8310

LOKI + IDUN + ODIN = THOR
1543 + 3082 + 5032 = 9657
1583 + 3042 + 5032 = 9657
2174 + 4693 + 1643 = 8510
2194 + 4673 + 1643 = 8510
3104 + 4567 + 1547 = 9218
3164 + 4507 + 1547 = 9218

const start = Date.now();
const solutions = [];

// no leading 0's, start at 1
for (let L = 1; L < 10; L++) {
  // no leading 0's, start at 1
  for (let O = 1; O < 10; O++) {
    for (let K = 0; K < 10; K++) {
      // no leading 0's, start at 1
      for (let I = 1; I < 10; I++) {
        for (let D = 0; D < 10; D++) {
          for (let U = 0; U < 10; U++) {
            for (let N = 0; N < 10; N++) {
              // no leading 0's, start at 1
              for (let T = 1; T < 10; T++) {
                for (let H = 0; H < 10; H++) {
                  for (let R = 0; R < 10; R++) {
                    const potentialSolution = {
                      L,
                      O,
                      K,
                      I,
                      D,
                      U,
                      N,
                      T,
                      H,
                      R
                    };

                    const loki = Number(`${L}${O}${K}${I}`);
                    const idun = Number(`${I}${D}${U}${N}`);
                    const odin = Number(`${O}${D}${I}${N}`);
                    const thor = Number(`${T}${H}${O}${R}`);

                    const uniqueNumbersUsed = new Set(
                      Object.values(potentialSolution)
                    );

                    if (
                      Object.values(potentialSolution).length ===
                      uniqueNumbersUsed.size
                    ) {
                      if (loki + idun + odin === thor) {
                        console.log(
                          `Found solution after ${Date.now() - start}ms`,
                          potentialSolution
                        );
                        solutions.push(potentialSolution);
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

console.log({ solutions });
console.log(`Duration: ${Date.now() - start}ms`);