题目:
Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
For example, given the following matrix:
[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]
You should return [1,2,3,6,9,8,7,4,5].
解决方案:
public ArrayList<Integer> spiralOrder(int[][] matrix){
ArrayList<Integer> result=new ArrayList<Integer>();
if(matrix==null||matrix.length==0)return result;
int m=matrix.length;
int n=matrix[0].length;
int x=0;
int y=0;
while(m>0&&n>0){
if(m==1){
for(int i=0;i<n;i++)
result.add(matrix[x][y++]);
return result;
}
else if(n==1){
for(int i=0;i<m;i++)
result.add(matrix[x++][y]);
return result;
}
for(int i=0;i<n-1;i++){
result.add(matrix[x][y++]);
}
for(int i=0;i<m-1;i++){
result.add(matrix[x++][y]);
}
for(int i=0;i<n-1;i++){
result.add(matrix[x][y--]);
}
for(int i=0;i<m-1;i++){
result.add(matrix[x--][y]);
}
x++;
y++;
n=n-2;
m=m-2;
}
return result;
}