LeetCode Reshape the Matrix

最新推荐文章于 2022-08-28 14:48:44 发布

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最新推荐文章于 2022-08-28 14:48:44 发布

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介绍了一种类似于MATLAB中'reshape'功能的算法实现，该算法能够将一个二维数组重塑为指定行数和列数的新矩阵，同时保持原始数据不变。如果重塑操作合法，则输出重塑后的矩阵；否则返回原始矩阵。

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In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into a new one with different size but keep its original data.

You're given a matrix represented by a two-dimensional array, and two positive integers r and c representing the row number and column number of the wanted reshaped matrix, respectively.

The reshaped matrix need to be filled with all the elements of the original matrix in the same row-traversing order as they were.

If the 'reshape' operation with given parameters is possible and legal, output the new reshaped matrix; Otherwise, output the original matrix.

Example 1:

Input: 
nums = 
[[1,2],
 [3,4]]
r = 1, c = 4
Output: 
[[1,2,3,4]]
Explanation:
The row-traversing of nums is [1,2,3,4]. The new reshaped matrix is a 1 * 4 matrix, fill it row by row by using the previous list.

Example 2:

Input: 
nums = 
[[1,2],
 [3,4]]
r = 2, c = 4
Output: 
[[1,2],
 [3,4]]
Explanation:
There is no way to reshape a 2 * 2 matrix to a 2 * 4 matrix. So output the original matrix.

Note:

The height and width of the given matrix is in range [1, 100].
The given r and c are all positive.

class Solution {
    public int[][] matrixReshape(int[][] nums, int r, int c) {
        int n = nums.length, m = nums[0].length;
    if (r*c != n*m) return nums;
    int[][] res = new int[r][c];
    for (int i=0;i<r*c;i++) 
        res[i/c][i%c] = nums[i/m][i%m];
    return res;
    }
}