找路径 带障碍

/**
* Created by xialei on 15/10/9.
* 也属于动态规划
*/
public class PathZhangai {
public static void main(String[] args){

}
public int uniquePathsWithObstacles(int[][] obstacleGrid) {
int m = obstacleGrid.length;     //获取数组行数
int n = obstacleGrid[0].length;  //获取数组列数
int[][] a = new int[m]
;       //存放路径
a[0][0] = 1;
if(obstacleGrid[0][0]==1){
return 0;
}
if(m==0 || n==0){
return 0;
}
for (int i = 1 ; i < m ; i++){
a[i][0] = a[i-1][0] & (obstacleGrid[i][0]==0?1:0);
}
for(int j = 1 ; j < n ; j++ ){
a[0][j] = a[0][j-1] & (obstacleGrid[0][j]==0?1:0);
}
for (int i = 1 ;i < m ;i++){
for(int j = 1 ; j < n ;j++){
if(obstacleGrid[i][j] == 0){
a[i][j]=a[i-1][j]+a[i][j-1];
}
else{
a[i][j]= 0;
}
}
}
return a[m-1][n-1];
}
}