Unique Paths

动态规划

    int uniquePaths(int m, int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(m==0||n==0)
            return 0;
        
        vector<vector<int> > pathCounts;
        
        int i,j;
  
        for(i=0;i<m;i++)
            pathCounts.push_back(vector<int>(n));
            
        for(j=0;j<n;j++)
            pathCounts[0][j] = 1;
        
        for(i=1;i<m;i++)
            pathCounts[i][0] = 1;
            
        for(i=1;i<m;i++)
            for(j=1;j<n;j++)
                pathCounts[i][j] = pathCounts[i-1][j]+pathCounts[i][j-1];
     
        return pathCounts[m-1][n-1];
    }