leetcode-----73

Set Matrix Zeros //code in java class Solution { public void setZeroes(int[][] matrix) { final int m = matrix.length; final int n = matrix[0].length; boolean shouldFillFirstRow = false; boolean shouldFillFirstCol = false;

for (int j = 0; j < n; ++j)
  if (matrix[0][j] == 0) {
    shouldFillFirstRow = true;
    break;
  }

for (int i = 0; i < m; ++i)
  if (matrix[i][0] == 0) {
    shouldFillFirstCol = true;
    break;
  }

// Store the information in the first row and the first column.
for (int i = 1; i < m; ++i)
  for (int j = 1; j < n; ++j)
    if (matrix[i][j] == 0) {
      matrix[i][0] = 0;
      matrix[0][j] = 0;
    }

// Fill 0s for the matrix except the first row and the first column.
for (int i = 1; i < m; ++i)
  for (int j = 1; j < n; ++j)
    if (matrix[i][0] == 0 || matrix[0][j] == 0)
      matrix[i][j] = 0;

// Fill 0s for the first row if needed.
if (shouldFillFirstRow)
  for (int j = 0; j < n; ++j)
    matrix[0][j] = 0;

// Fill 0s for the first column if needed.
if (shouldFillFirstCol)
  for (int i = 0; i < m; ++i)
    matrix[i][0] = 0;

} }