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].
public static List spiralOrder(int[][] matrix) {
ArrayList result=new ArrayList();
if(matrix.length==0){
return result;
}
int row=matrix.length;
if(matrix[0].length==0){
return result;
}
int column=matrix[0].length;
int times=2*(Math.min(row, column)-1)+1;
int [][]flag=new int[row][column];
int m=0,n=0;
//行数多的话多遍历一次
if(row>column)
times++;
//先加到集合中在管下一个
result.add(matrix[0][0]);
//加到集合中要标记用过了
flag[m][n]=1;
for(int i=0;i
switch (i%4) {
case 0:
n++;
while(n
result.add(matrix[m][n]);
flag[m][n]=1;
n++;
}
n--;
break;
case 1:
m++;
while(m
result.add(matrix[m][n]);
flag[m][n]=1;
m++;
}
m--;
break;
case 2:
n--;
while(n>=0&&flag[m][n]==0){
result.add(matrix[m][n]);
flag[m][n]=1;
n--;
}
n++;
break;
default:
m--;
while(m>=0&&flag[m][n]==0){
result.add(matrix[m][n]);
flag[m][n]=1;
m--;
}
m++;
break;
}
}
return result;
}
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