[LeetCode]Unique Paths II

class Solution {
//DP
//if a[i][j] is a obstacle, then f[i][j]=0
public:
int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int m = obstacleGrid.size();
if(0 == m) return 0;
int n = obstacleGrid[0].size();
vector<vector<int>> f(m+1, vector<int>(n+1, 0));
if(obstacleGrid[0][0] != 1)
f[1][1] = 1;
for (int i = 1; i <= m; ++i)
{
for (int j = 1; j <= n; ++j)
{
if(i == 1 && j == 1) continue;
if(0 == obstacleGrid[i-1][j-1])//empty
f[i][j] = f[i-1][j]+f[i][j-1];
}
}
return f[m]
;
}
};

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();
if(m == 0) return 0;
int n = obstacleGrid[0].size();

vector<vector<int> > f(m+1, vector<int>(n+1, 0));
for(int i = 1; i <= m; ++i)
{
for(int j = 1; j <= n; ++j)
{
if(obstacleGrid[i-1][j-1] == 1) continue;

if(i == 1 && j == 1) f[i][j] = 1;
else f[i][j] = f[i-1][j]+f[i][j-1];
}
}
return f[m]
;
}
};