题目描述
Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.
Example:
Input: 3 Output: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]
class Solution {
public:
vector<vector<int>> generateMatrix(int n) {
vector<vector<int>> res(n, vector<int>(n));
int num = 1;
int cycle = (min(n, n) - 1) / 2 + 1;
for(int i = 0; i < cycle; i++){
for(int j = i; j < n - i; j++){
res[i][j] = num++;
}
for(int j = i + 1; j < n - i; j++){
res[j][n - i - 1] = num++;
}
for(int j = n - i - 2; j >= i && n - i - 1 != i; j--){
res[n - i - 1][j] = num++;
}
for(int j = n - i - 2; j > i && n - j - 1 != i; j--){
res[j][i] = num++;
}
}
return res;
}
};
