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] ]
The total number of unique paths is 2
.
Note: m and n will be at most 100.
解题报告:Unique Paths II 是Unique Paths 的升级版,多一个数组存了1代表障碍这点走不通,所以我们解决的时候,也要多一步判断。不难
class Solution { public: int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) { size_t m = obstacleGrid.size(); size_t n = obstacleGrid[0].size(); int temp[m][n]; for (size_t i = 0; i != m; i++) for(size_t j = 0; j != n; j++) temp[i][j] = 0; temp[0][0] = 1; for (size_t i = 0; i != m; i++) { for(size_t j = 0; j != n; j++) { if(obstacleGrid[i][j] != 1) { if(j != n-1) { if(temp[i][j+1] != -1) temp[i][j+1] += temp[i][j]; else temp[i][j+1] = temp[i][j]; }} else temp[i][j] = 0; if(obstacleGrid[i][j] != 1) { if(i != m-1) { if(temp[i+1][j] != -1) temp[i+1][j] += temp[i][j]; else temp[i+1][j] = temp[i][j] ; }} else temp[i][j] = 0 ; } } return temp[m-1][n-1]; } };
原文:http://blog.csdn.net/vanish_dust/article/details/42748817