Question 302648 in Javascript Question posted in
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Javascript – How to simplify this nested code with lots of loops

I’m struggling to simplify a piece of nested code, without success, though.

Every time I have to deal with recursion, I’m having a hard time. If anyone can help me with that, I’ll be really happy 🙂

Here’s the beast :

const solutions: Solution[] = []

for (const sol of [currentSolution]) {
    const solutionsFirstPieceOnly = findSolutionsWithOneMorePiece({currentSolution: sol, pieceSet: currentPieceSet})
    for (const sol1 of solutionsFirstPieceOnly) {
        const solutionsSecondRank = findSolutionsWithOneMorePiece({currentSolution: sol1, pieceSet: currentPieceSet})
        for (const sol2 of solutionsSecondRank) {
            const solutionsThirdRank = findSolutionsWithOneMorePiece({currentSolution: sol2, pieceSet: currentPieceSet})
            for (const sol3 of solutionsThirdRank) {
                const solutionsFourthRank = findSolutionsWithOneMorePiece({currentSolution: sol3, pieceSet: currentPieceSet})
                for (const sol4 of solutionsFourthRank) {
                    const solutionsFifthRank = findSolutionsWithOneMorePiece({currentSolution: sol4, pieceSet: currentPieceSet})
                    for (const sol5 of solutionsFifthRank) {
                        const solutionsSixthRank = findSolutionsWithOneMorePiece({currentSolution: sol5, pieceSet: currentPieceSet})
                        for (const sol6 of solutionsSixthRank) {
                            const solutionsSeventhRank = findSolutionsWithOneMorePiece({currentSolution: sol6, pieceSet: currentPieceSet})
                            for (const sol7 of solutionsSeventhRank) {
                                const solutionsEighthRank = findSolutionsWithOneMorePiece({currentSolution: sol7, pieceSet: currentPieceSet})
                                for (const sol8 of solutionsEighthRank) {
                                    const solutionsNinethRank = findSolutionsWithOneMorePiece({currentSolution: sol8, pieceSet: currentPieceSet})
                                    solutionsNinethRank.forEach((solution) => {if (solution.length) solutions.push(solution)})
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

console.log(solutions)
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2

Answers


  1. 0

    You could try make a function that you can use recursively. This way you should be able to achieve the same function as the code in the question.

    function findSolutionsRecursive(currentSolution, pieceSet, depth, maxDepth) {
    if (depth === maxDepth) {
        return [currentSolution];
    } else {
        let solutions = [];
        const nextSolutions = findSolutionsWithOneMorePiece({ currentSolution, pieceSet });

        for (const nextSolution of nextSolutions) {
            solutions = solutions.concat(findSolutionsRecursive(nextSolution, pieceSet, depth + 1, maxDepth));
        }

        return solutions;
    }
}

const maxDepth = 9;
const solutions = findSolutionsRecursive(currentSolution, currentPieceSet, 0, maxDepth);

    Code is not tested, but might work, or should be able to give you an idea for an approacht

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  2. 0

    This is a good candidate for a (recursive) generator function:

    function* iter(solutions: Solution[], pieceSet, remaining=9) {
    if (remaining == 0) {
        yield* solutions.filter(({length}) => length);
        return;  
    }
    remaining--;
    for (const currentSolution of solutions) {
        const newSolutions = findSolutionsWithOneMorePiece({currentSolution, pieceSet});
        yield* iter(newSolutions, pieceSet, remaining);
    }
}

const solutions: Solution[] = [...iter([currentSolution], currentPieceSet)];
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