Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
Example 1:
Input: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] Output: [1,2,3,6,9,8,7,4,5] Example 2:
Input: [ [1, 2, 3, 4], [5, 6, 7, 8], [9,10,11,12] ] Output: [1,2,3,4,8,12,11,10,9,5,6,7]
public class Solution {
public IList<int> SpiralOrder(int[][] matrix) {
var res = new List<int>();
if(matrix.Length==0){
return res;
}
int sx = 0;
int ex = matrix.Length;
int sy = 0;
int ey = matrix[0].Length;
while (sx<ex && sy<ey){
for(int i=sy;i<ey;i++){
res.Add(matrix[sx][i]);
}
sx++;
for(int i= sx;i<ex;i++){
res.Add(matrix[i][ey-1]);
}
ey--;
if(sx<ex){
for(int i= ey-1;i>=sy;i--){
res.Add(matrix[ex-1][i]);
}
}
ex--;
if(sy<ey){
for(int i=ex-1;i>=sx;i--){
res.Add(matrix[i][sy]);
}
}
sy++;
}
return res;
}
}Time Complexity: O(n^2)
Space Complexity: O(1)
