if(matrix.size() < 2) return;

std::vector<int> vec;

int i = 0, iEnd = matrix.size() - 1, j = 0, jEnd = matrix[0].size() - 1;

for(int i = 0, iEnd = matrix.size() - 1, j = 0, jEnd = matrix[0].size() - 1;

i < iEnd && j < jEnd; ++i, ++j, --iEnd, --jEnd)

{

vec.clear();

//存第一行

for(int k = j; k <= jEnd; ++k)

vec.emplace_back(matrix[i][k]);

//left -> top

for(int m = i + 1, n = jEnd - 1;m <= iEnd && n >= j; ++m, --n)

matrix[i][n] = matrix[m][j];

//down ->left

for(int m = i+1, n = j+1;m <= iEnd && n <= jEnd; ++m, ++n)

matrix[m][j] = matrix[iEnd][n];

//right->down

for(int m = iEnd-1, n = j + 1;m >i && n < jEnd; --m, ++n)

matrix[iEnd][n] = matrix[m][jEnd];

//top->right

for(int m = i; m <= iEnd; ++m)

matrix[m][jEnd] = vec[m-i];

}

return;

{

if (matrix.empty() || matrix.back().empty() || matrix.size() == 1) return;

const int N = (int)matrix.size();

for (int i = 0, iEnd = N / 2; i < iEnd; ++i)

{

for (int k = 0, kEnd = N - i * 2 - 1; k < kEnd; ++k)

{

std::swap(matrix[i][i + k], matrix[i+k][N-i-1]);

std::swap(matrix[i][i + k], matrix[N-i-1][N-i-k-1]);

std::swap(matrix[i][i + k], matrix[N-i-k-1][i]);

}

}