/**
 * @param {number[][]} obstacleGrid
 * @return {number}
 */
var uniquePathsWithObstacles = function (obstacleGrid) {
  var m = obstacleGrid.length;
  var n = obstacleGrid[0].length;

  var dp = [];
  for (var i = 0; i < m; i  ) {
    dp[i] = [];
  }

  if (obstacleGrid[0][0] == 1) {
    dp[0][0] = 0;
  } else {
    dp[0][0] = 1;
  }
  for (var i = 1; i < m; i  ) {
    dp[i][0] = (obstacleGrid[i][0] == 1) ? 0 : dp[i - 1][0];
  }

  for (var j = 1; j < n; j  ) {
    dp[0][j] = obstacleGrid[0][j] == 1 ? 0 : dp[0][j - 1];
  }

  for (var i = 1; i < m; i  ) {
    for (var j = 1; j < n; j  ) {
      dp[i][j] = obstacleGrid[i][j] == 1 ? 0 : dp[i - 1][j]   dp[i][j - 1];
    }
  }
  return obstacleGrid[m - 1][n - 1] == 1 ? 0 : dp[m - 1][n - 1];
};