[LeedCode OJ]#63 Unique Paths II

class Solution
{
public:
    int uniquePathsWithObstacles(vector<vector<int> >& a)
    {
        int i,j;
        int n = a.size(),m = a[0].size();
        vector<vector<int> > dp;
        dp.resize(n+1);
        for(i = 0; i<=n; i++)
            dp[i].resize(m+1);
        dp[0][0] = !a[0][0];
        for(i = 0; i<n; i++)
        {
            for(j = 0; j<m; j++)
            {
                if(i==0&&j==0) continue;
                if(a[i][j]==1)
                {
                    dp[i][j] = 0;
                    continue;
                }
                if(i == 0)
                {
                    dp[i][j]=dp[i][j-1];
                    continue;
                }
                if(j == 0)
                {
                    dp[i][j]=dp[i-1][j];
                    continue;
                }
                dp[i][j]=dp[i-1][j]+dp[i][j-1];
            }
        }
        return dp[n-1][m-1];
    }
};