LeetCode-Unique Paths II

Follow up for "Unique Paths":

Now consider if some obstacles are added to the grids. How many unique paths would there be?

An obstacle and empty space is marked as 1 and 0 respectively in the grid.

For example,

There is one obstacle in the middle of a 3x3 grid as illustrated below.

[
  [0,0,0],
  [0,1,0],
  [0,0,0]
]

The total number of unique paths is 2.

Note: m and n will be at most 100.

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<long long>> dp;
        
        for(unsigned int i=0;i<obstacleGrid.size();i++){
            vector<long long>row;
            for(unsigned int j=0;j<obstacleGrid[0].size();j++){
                row.push_back(0);
            }
            dp.push_back(row);
        }
        dp[0][0]=1;
         for(unsigned int i=0;i<obstacleGrid.size();i++){
            for(unsigned int j=0;j<obstacleGrid[0].size();j++){
                if(!obstacleGrid[i][j]){
                    if(i>0)dp[i][j]+=dp[i-1][j];
                    if(j>0)dp[i][j]+=dp[i][j-1];
                }
                else dp[i][j]=0;
            }
        }
        return dp[obstacleGrid.size()-1][obstacleGrid[0].size()-1];
    }
};