59>spiralNumbers

Construct a square matrix with a size N × N containing integers from 1 to N * N in a spiral order, starting from top-left and in clockwise direction. Example For n = 3, the output should be spiralNumbers(n) = [[1, 2, 3],                     [8, 9, 4],                     [7, 6, 5]]

code>>

std::vector<std::vector<int>> spiralNumbers(int n) {

std::vector<std::vector<int>> _list;

for (int i = 0; i < n; i++)

_list.push_back(std::vector<int>(n));

int x = -1, y = 0, idx = 1;

int jump = 1, max = n *n;

while (idx <= max)

{

for (int i = 0; i < n; i++)

{

x += jump;

_list[y][x] = idx++;

}

for (int i = 0; i < n - 1; i++)

{

y += jump;

_list[y][x] = idx++;

}

jump *= -1;

n--;

}

return _list;

}