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Rotate_Image.js
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Rotate_Image.js
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// ----------------------------Description------------------------------------
// You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
// You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
// Example 1:
// Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
// Output: [[7,4,1],[8,5,2],[9,6,3]]
// Example 2:
// Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
// Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
// Constraints:
// n == matrix.length == matrix[i].length
// 1 <= n <= 20
// -1000 <= matrix[i][j] <= 1000
// ---------------------------------------------------------------------------
const rotate = (matrix) => {
const n = matrix.length;
// Iterate through each layer
for (let layer = 0; layer < Math.floor(n / 2); layer++) {
const first = layer;
const last = n - 1 - layer;
// Iterate through each element in the layer
for (let i = first; i < last; i++) {
// Save the top element
const top = matrix[first][i];
// Move left to top
matrix[first][i] = matrix[last - (i - first)][first];
// Move bottom to left
matrix[last - (i - first)][first] = matrix[last][last - (i - first)];
// Move right to bottom
matrix[last][last - (i - first)] = matrix[i][last];
// Move top to right
matrix[i][last] = top;
}
}
};
// Example usage:
const matrix1 = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];
const matrix2 = [
[5, 1, 9, 11],
[2, 4, 8, 10],
[13, 3, 6, 7],
[15, 14, 12, 16]
];
rotate(matrix1);
rotate(matrix2);
console.log("Rotated matrix 1:");
matrix1.forEach(row => console.log(row));
console.log("Rotated matrix 2:");
matrix2.forEach(row => console.log(row));