Input: [ [0,0,0], [0,1,0], [0,0,0] ] Output: 2 Explanation: There is one obstacle in the middle of the 3x3 grid above. There are two ways to reach the bottom-right corner: 1. Right -> Right -> Down -> Down 2. Down -> Down -> Right -> Right
class Solution {
public:int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
int m=obstacleGrid.size();
// if(m<=0){
// return 0;
// }
int n=obstacleGrid[0].size();
// if(m==1&&n==1){
// if(obstacleGrid[0][0]==1){
// return 0;
// }else{
// return 1;
// }
// }
vector<vector<int> > dp(m,vector<int>(n,0));// dp(i,j) 表示到达i,j 的总种树
for(int i=0;i<m;++i){
if(obstacleGrid[i][0]==0){
dp[i][0]=1;
}else{
break;
}
}
for(int i=0;i<n;++i){
if(obstacleGrid[0][i]==0){ // 不是障碍物
dp[0][i]=1;
}else{
break;
}
}
for(int i=1;i<m;++i){
for(int j=1;j<n;++j){
if(obstacleGrid[i][j]==0){
dp[i][j]=dp[i-1][j]+dp[i][j-1];
}else{
dp[i][j]=0;
}
}
}
return dp[m-1][n-1];
}
};