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]
]

he 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
int m = obstacleGrid.size();
int n = obstacleGrid[0].size();
vector<vector<int>> grid(m, vector<int>(n,0));
for(int i = 0; i< n; i++)
if(obstacleGrid[0][i] ==0) grid[0][i] = 1;
else break;
for(int i = 0; i< m; i++)
if(obstacleGrid[i][0] == 0) grid[i][0] = 1;
else break;

for(int i = 1; i< m; i++)
for(int j = 1; j< n; j++)
if(obstacleGrid[i][j] == 0)
grid[i][j] = grid[i-1][j] + grid[i][j-1];

return grid[m-1][n-1];
}
};