"Primary algorithm" 11. Rotate the image

Topic:

given a nxn, a two-dimensional matrix represents an image. Rotate the image clockwise -degree. Note: You must rotate the image in place, which means you need to modify the input two-dimensional matrix directly. Do not use another matrix to rotate the image. Example1: Given the matrix= [  [1,2,3],  [4,5,6],  [7,8,9] ], rotate the input matrix in place so that it becomes: [[7,4,1],  [8,5,2],  [9,6,3]] Example2: Given the matrix=[  [ 5,1,9, One],  [ 2,4,8,Ten],  [ -,3,6,7],  [ the, -, A, -] ], rotate the input matrix in place so that it becomes: [[ the, -,2,5],  [ -,3,4,1],  [ A,6,8,9],  [ -,7,Ten, One]]

Problem Solving Ideas:

1. Rotate each of these layers:

classSolution { Public:   voidRotate (vector<vector<int> > &matrix) {        intn =matrix.size ();  for(inti =0; I < n/2; ++i) { for(intj = i; J < N-1I ++j) {intTMP =Matrix[i][j]; MATRIX[I][J]= Matrix[n-1-J]                [i]; Matrix[n-1-J][i] = matrix[n-1-I][n-1-J]; Matrix[n-1-I][n-1-j] = Matrix[j][n-1-i]; Matrix[j][n-1-I] =tmp; }        }    }};

2. Transpose the matrix, then swap right and left.

class Solution {public:    void rotate (vector<vector<int> > &Matrix) {         int n = matrix.size ();          for (int0; i < n; + +i)            {for (int1; j < n; ++<
   
     C20>J) {                swap (matrix[i][j], matrix[j][i]);            }            Reverse (Matrix[i].begin (), Matrix[i].end ());}}           ;
   

Primary algorithm 11. Rotate the image