给定一个?n?×?n?的二维矩阵?matrix
?表示一个图像。请你将图像顺时针旋转 90 度。
你必须在?原地?旋转图像,这意味着你需要直接修改输入的二维矩阵。请不要?使用另一个矩阵来旋转图像。
示例 1:
输入:matrix = [[1,2,3],[4,5,6],[7,8,9]] 输出:[[7,4,1],[8,5,2],[9,6,3]]
示例 2:
输入:matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]] 输出:[[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
提示:
n == matrix.length == matrix[i].length
1 <= n <= 20
-1000 <= matrix[i][j] <= 1000
方法1:(0ms)
public static void rotate(int[][] matrix) {
int n = matrix.length;
int row = 0;
int col = n - 1;
int index = 0;
while (row < col){
while (row + index < col) {
int leftUp = matrix[row][row + index];
int rightUp = matrix[row + index][col];
int rightDown = matrix[col][col - index];
int leftDown = matrix[col - index][row];
matrix[row][row + index] = leftDown;
matrix[row + index][col] = leftUp;
matrix[col][col - index] = rightUp;
matrix[col - index][row] = rightDown;
index++;
}
index = 0;
row++;
col--;
}
}