73.js

/** ------------------------------------------------------------------------------
 * 
 * 73. Set Matrix Zeroes
 * Topics: Matrix, Hash Table
 * https://leetcode.com/problems/set-matrix-zeroes/description/?envType=daily-question&envId=2025-05-21
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
// var setZeroes = function (matrix) {
//   const rowIndexOfZero = new Set();
//   const colIndexOfZero = new Set();
//   // iterate over matrix
//   matrix.forEach((row, rowIdx) => {
//     row.forEach((col, colIdx) => {
//       if (matrix[rowIdx][colIdx] === 0) {
//         rowIndexOfZero.add(rowIdx);
//         colIndexOfZero.add(colIdx);
//       }
//     });
//   });
//   const rowLen = matrix.length;
//   const colLen = matrix[0].length;

//     for(let row=0; row<rowLen; row++){
//         for(let col=0; col<colLen; col++){
//             if(rowIndexOfZero.has(row) || colIndexOfZero.has(col)){
//                 matrix[row][col] = 0
//             }
//         }
//     }
// };

var setZeroes = function (matrix) {
  const rows = matrix.length - 1
  const cols = matrix[0].length - 1

  let isFirstRowZeroes = false

  for (let r = 0; r <= rows; r++) {
    for (let c = 0; c <= cols; c++) {
      const value = matrix[r][c]

      if (r === 0 && value === 0) {
        isFirstRowZeroes = true
        continue
      }

      if (value === 0) {
        matrix[r][0] = 0
        matrix[0][c] = 0
      }
    }
  }

  for (let r = 1; r <= rows; r++) {
    const value = matrix[r][0]

    if (value !== 0) continue

    for (let c = 1; c <= cols; c++) {
      matrix[r][c] = 0
    }
  }

  for (let c = 0; c <= cols; c++) {
    const value = matrix[0][c]

    if (value !== 0) continue

    for (let r = 1; r <= rows; r++) {
      matrix[r][c] = 0
    }
  }

  if (!isFirstRowZeroes) return

  for (let c = 0; c <= cols; c++) {
    matrix[0][c] = 0
  }
}

console.log(
  setZeroes([
    [1, 1, 1],
    [1, 0, 1],
    [1, 1, 1],
  ]),
)