function uniquePathsWithObstacles(grid) {
  const rows = grid.length;
  const cols = grid[0].length;
  const dp = new Array(cols).fill(0);
  dp[0] = grid[0][0] === 0 ? 1 : 0;
  for (let r = 0; r < rows; r++) {
    for (let c = 0; c < cols; c++) {
      if (grid[r][c] === 1) {
        dp[c] = 0;
      } else if (c > 0) {
        dp[c] += dp[c - 1];
      }
    }
  }
  return dp[cols - 1];
}