0566. Reshape the Matrix

# 566. Reshape the Matrix#

## 题目 #

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 crepresenting 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:

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

## 解题思路 #

• 给一个二维数组和 r，c，将这个二维数组“重塑”成行为 r，列为 c。如果可以“重塑”，输出“重塑”以后的数组，如果不能“重塑”，输出原有数组。
• 这题也是水题，按照题意模拟即可。

## 代码 #

``````
package leetcode

func matrixReshape(nums [][]int, r int, c int) [][]int {
if canReshape(nums, r, c) {
return reshape(nums, r, c)
}
return nums
}

func canReshape(nums [][]int, r, c int) bool {
row := len(nums)
colume := len(nums[0])
if row*colume == r*c {
return true
}
return false
}

func reshape(nums [][]int, r, c int) [][]int {
newShape := make([][]int, r)
for index := range newShape {
newShape[index] = make([]int, c)
}
rowIndex, colIndex := 0, 0
for _, row := range nums {
for _, col := range row {
if colIndex == c {
colIndex = 0
rowIndex++
}
newShape[rowIndex][colIndex] = col
colIndex++
}
}
return newShape
}

``````

Sep 6, 2020