螺旋矩阵

https://www.acwing.com/problem/content/1597/

#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>

using namespace std;

const int N = 10010;

int n;
int w[N];

int main()
{
    cin >> n;
    for (int i = 0; i < n; i ++ ) cin >> w[i];

    sort(w, w + n, greater<int>());

    int r, c;
    for (int i = 1; i <= n / i; i ++ )
        if (n % i == 0)
        {
            r = n / i;
            c = i;
        }

    vector<vector<int>> res(r, vector<int>(c));

    int dx[] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
    for (int i = 0, x = 0, y = 0, d = 1; i < n; i ++ )
    {
        res[x][y] = w[i];
        int a = x + dx[d], b = y + dy[d];
        if (a < 0 || a >= r || b < 0 || b >= c || res[a][b])
        {
            d = (d + 1) % 4;
            a = x + dx[d], b = y + dy[d];
        }
        x = a, y = b;
    }

    for (int i = 0; i < r; i ++ )
    {
        cout << res[i][0];
        for (int j = 1; j < c; j ++ )
            cout << ' ' << res[i][j];
        cout << endl;
    }

    return 0;
}