leetcode63 Unique Paths II

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.

class Solution {
public:
int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
int ans=0;
int m=obstacleGrid.size();
if(!m)
return ans;
int n=obstacleGrid[0].size();

vector<int> jlist(n,0);
for(int i=n-1;i>=0;i--)
{
if(obstacleGrid[m-1][i]==1)
break;
else
jlist[i]=1;
}

for(int i=m-2;i>=0;i--)
{
for(int j=n-1;j>=0;j--)
{
if(j==n-1)
{
if(obstacleGrid[i][j]==1)
jlist[j]=0;
}
else
{

if(obstacleGrid[i][j]==1)
jlist[j]=0;
else
jlist[j]+=jlist[j+1];

}

}
}
return jlist[0];
}
};

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