第4讲2*

#include <iostream>

using namespace std;

int res[100][100];

int main() 
{
    int n, m;
    cin >> n >> m;

    int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};//走的方向 /→:(0,1) dx[0]dy[0]  ↓:(1,0) dx[1]dy[1]  ←:(0,-1) dx[2]dy[2]  ↑:(-1,0) dx[3]dy[3]  /→(又回到右)

    for(int x = 0, y = 0, d = 0, k = 1; k <= n*m; k++) //k是填入的数字从1到n*m
    {
        res[x][y] = k;
        int a = x + dx[d], b = y + dy[d]; //移动
        if(a < 0 || a >= n || b < 0 || b >= m ||  res[a][b])//撞墙：出界(a<0 a>=n b<0 b>=m) 或重复(res[a][b]!=0)
        {
            d = (d+1) % 4; //换下一个方向
            a = x + dx[d], b = y + dy[d];
        }
        x = a, y = b;
    }

    for (int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++) cout << res[i][j] << ' ';
        cout << endl;
    }
    return 0;
}