LeetCode-Uniqpaths II

题目要求：
相比较于Unique Paths，多了一些限制，某些obstaclegrid=1的位置不能作为路径。
方法一样，采用动态规划，添加一些限制：
Method: flag[i][j] = obstacleGrid[i][j]==1? 0:flag[i-1][j]+flag[i][j-1];

class Solution {
public:
    void non_uniqpath(vector<vector<int>>& obstacleGrid,int& num){
        int m = obstacleGrid.size();
        int n = obstacleGrid[0].size();
        vector<vector<int>> flag;
        flag.resize(m);
        for_each(flag.begin(),flag.end(),[n](vector<int>& pa){pa.resize(n,0);});
        flag[0][0] = obstacleGrid[0][0]==1? 0:1;
        for (int i=1;i<n;i++){
            flag[0][i] = obstacleGrid[0][i]==1? 0:flag[0][i-1];
        }
        for (int i=1;i<m;i++){
            flag[i][0] = obstacleGrid[i][0]==1? 0:flag[i-1][0];
        }
        for (int i=1;i<m;i++){
            for (int j=1;j<n;++j){
                flag[i][j] = obstacleGrid[i][j]==1? 0:flag[i-1][j]+flag[i][j-1];
            }
        }
        num = flag[m-1][n-1];
    }
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int num=0;
        non_uniqpath(obstacleGrid,num);
        return num;
    }
};