Two-Dimensional Array Traversal Tetris Block Fall Drop https://codesignal.com/blog/interview-prep/example-codesignal-questions https://jsfiddle.net/45th1rqo/ https://jsfiddle.net/kvboemqL/1/

drop.js

// Check if the figure can be placed at a specific row and column
const canPlaceFigure = (figure, field, startRow, startCol) => {
    for (let i = 0; i < figure.length; i++) {
        for (let j = 0; j < figure[0].length; j++) {
            if (figure[i][j] === 1 && field[startRow + i][startCol + j] === 1) {
                return false; // Conflict detected
            }
        }
    }
    return true; // Placement is possible
};

// Merge the figure into the field at a specific position
const mergeFigure = (figure, field, startRow, startCol) => {
    const newField = JSON.parse(JSON.stringify(field)); // Create a deep copy
    for (let i = 0; i < figure.length; i++) {
        for (let j = 0; j < figure[0].length; j++) {
            if (figure[i][j] === 1) {
                newField[startRow + i][startCol + j] = 1;
            }
        }
    }
    return newField;
};

// Check if any row in the field is fully occupied
const hasFullRow = (field) => {
    for (let row = 0; row < field.length; row++) {
        if (field[row].every(cell => cell === 1)) {
            return true; // Full row found
        }
    }
    return false; // No full rows
};

// Calculate the landing row for the figure in a given column
const dropCol = (figure, field, column) => {
    const maxRow = field.length - figure.length;
    for (let row = 0; row <= maxRow; row++) {
        if (!canPlaceFigure(figure, field, row, column)) {
            return row - 1; // Figure landed above the conflict
        }
    }
    return field.length - figure.length; // Figure landed at the bottom
};

// Find the best column to drop the figure
const drop = (figure, field) => {
    const fieldWidth = field[0].length;
    const figureWidth = figure[0].length;
    const maxDropCol = fieldWidth - figureWidth + 1;

    for (let col = 0; col < maxDropCol; col++) {
        const landingRow = dropCol(figure, field, col);
        if (landingRow !== -1) {
            const newField = mergeFigure(figure, field, landingRow, col);
            if (hasFullRow(newField)) {
                return col; // Found a valid column
            }
        }
    }

    return -1; // No valid column found
};

field = [[0, 0, 0],
         [0, 0, 0],
         [0, 0, 0],
         [1, 0, 0],
         [1, 1, 0]];
         
figure = [[0, 0, 1],
          [0, 1, 1],
          [0, 0, 1]];
          
console.log(drop(figure, field));

field =  [[0, 0, 0, 0, 0],
          [0, 0, 0, 0, 0],
          [0, 0, 0, 0, 0],
          [1, 1, 0, 1, 0],
          [1, 0, 1, 0, 1]];
          
figure = [[1, 1, 1],
          [1, 0, 1],
          [1, 0, 1]];
          
console.log(drop(figure, field));