Find all numbers a and b with distinct digits where a-b=42137

findNumbers.test.ts

describe("numbertest", () => {

    const digitsOf = (n: number): number[] => {
        const digits = [];
        const s = n.toString();
        for (let i = 0; i < s.length; i++) {
            const digit = parseInt(s.charAt(i));
            digits.push(digit);
        }
        return digits;
    }

    const containsEachDigitOnce = (digits: number[]): boolean => {
        return digits.indexOf(0) === -1 && new Set(digits).size === digits.length;
    }

    const containEachDigitOnce = (first: number, second: number): boolean => {
        const joinedDigits = digitsOf(first).concat(digitsOf(second));
        return containsEachDigitOnce(joinedDigits);
    }

    it("find all numbers with the result where each digit 1-9 only occurrs once", () => {
        const solutions = [];
        const substractionResult = 42137;
        for (let first = substractionResult; first < substractionResult + 10000; first++) {
            if (containsEachDigitOnce(digitsOf(first))) {
                for (let second = 1000; second < 9999; second++) {
                    if (containEachDigitOnce(first, second)) {
                        if (first - second === substractionResult) {
                            solutions.push(`${first}-${second}=${substractionResult}`);
                        }
                    }
                }
            }
        }
        console.log(solutions);
    })
});

zu kompliziert :(