LeetCode867. Transpose Matrix

Given a matrix A, return the transpose of A.

The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix.

Example 1:

Input: [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]

Example 2:

Input: [[1,2,3],[4,5,6]]
Output: [[1,4],[2,5],[3,6]]

Note:

1. 1 <= A.length <= 1000
2. 1 <= A[0].length <= 1000

题目非常简单，就是将数组转置。

int x=[](){
   std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
public:
    vector<vector<int>> transpose(vector<vector<int>>& A) {
        vector<int> temp;
        vector<vector<int> >B;
        int m=A.size();//row
        int n=A[0].size();//column
        int i,j;
        for(j=0;j<n;j++)
            for(i=0;i<m;i++)
            temp.push_back(A[i][j]);

        B.resize(n);
        for(i=0;i<n;i++)
            B[i].resize(m);
        int k=0;
        for(i=0;i<n;i++)
            for(j=0;j<m;j++)
            {
                B[i][j]=temp[k];
                k++;
            }
        return B;
    }
};

思考进行优化：

int x=[](){
   std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
public:
    vector<vector<int>> transpose(vector<vector<int>>& A) {
        vector<vector<int> >B;
        int m=A.size();//row
        int n=A[0].size();//column
        int i,j;
        for(j=0;j<n;j++)
        {
            vector<int> temp;
            for(i=0;i<m;i++)
            {
                temp.push_back(A[i][j]);
            }
            B.push_back(temp);
        }

        return B;
    }
};