public int uniquePathsWithObstacles(int[][] grid) {

return dfs(

grid,

0,

0,

grid.length,

grid[0].length,

new int[grid.length][grid[0].length]

);

}

public int dfs(int[][] grid, int i, int j, int m, int n, int[][] dp) {

if (i < 0 || j < 0 || i >= m || j >= n || grid[i][j] == 1) {

return 0;

}

if (i == m - 1 && j == n - 1) {

dp[i][j] = 1;

return dp[i][j];

}

if (dp[i][j] != 0) return dp[i][j];

int right = dfs(grid, i, j + 1, m, n, dp);

int left = dfs(grid, i + 1, j, m, n, dp);

dp[i][j] = right + left;

return dp[i][j];

}