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reshape-the-matrix

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Reshape the Matrix – LeetCode 566

Problem

Description

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.

Answer

Original

Code

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class Solution {
public:
    vector<vector<int>> matrixReshape(vector<vector<int>>& nums, int r, int c) {
        if(r * c != nums.size() * nums[0].size())
            return nums;
        int pos = 0;
        vector<vector<int>> result;
        for(int x = 0; x != nums.size(); ++x){
            for(int y = 0; y != nums[0].size(); ++y, ++pos){
                if(pos % c == 0)
                    result.push_back(vector<int>{nums[x][y]});
                else
                    result[pos / c].push_back(nums[x][y]);
            }
        }
        return result;
    }
};

思路

简单的构造。时间复杂度$O(m \times n)$，空间复杂度$O(m \times n)$。
耗时$24$ ms，排名$3.47\%$

Better

思路

还没看到更好的思路。