问题描述:
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 ]
]
题源:here;完整实现:here
思路:
方法同第54题,我们一层一层的构造螺旋矩阵,代码如下:
class Solution {
public:
vector<vector<int>> generateMatrix(int n) {
vector<vector<int>> result(n, vector<int>(n));
int left = 0, right = n - 1, top = 0, bottom = n - 1;
int count = 1;
while (left <= right){
for (int i = left; i <= right; i++) result[top][i] = count++;
if (left < right){
for (int i = top + 1; i < bottom; i++) result[i][right] = count++;
for (int i = right; i > left; i--) result[bottom][i] = count++;
for (int i = bottom; i > top; i--) result[i][left] = count++;
}
left++; right--; top++; bottom--;
}
return result;
}
};