三维数组

#include <bits/stdc++.h>
using namespace std;
int n, m;
// [天数][行][列]
char g[105][105][105];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            cin >> g[1][i][j];
    cin >> m;
    for (int day = 2; day <= m; day++)
    {
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
            {
                if (g[day - 1][i][j] == '#')
                    g[day][i][j] = '#';
                else if (g[day - 1][i - 1][j] == '@' ||
                         g[day - 1][i][j - 1] == '@' || g[day - 1][i][j] == '@' || g[day - 1][i][j + 1] == '@' ||
                         g[day - 1][i + 1][j] == '@')
                    g[day][i][j] = '@';
            }
    }
    int cnt = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (g[m][i][j] == '@')
                cnt++;
    cout << cnt << "\n";
    return 0;
}

两个二维数组滚动

#include <bits/stdc++.h>
using namespace std;
int n, m;
// [天数][行][列]
char a[105][105];
char b[105][105];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            cin >> a[i][j];
    cin >> m;
    for (int day = 2; day <= m; day++)
    {
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
            {
                if (a[i][j] == '#')
                    b[i][j] = '#';
                else if (a[i - 1][j] == '@' ||
                         a[i][j - 1] == '@' || 
						 a[i][j] == '@' || 
						 a[i][j + 1] == '@' ||
                         a[i + 1][j] == '@')
                    b[i][j] = '@';
            }
        for(int i=1;i<=n;i++)
        	for(int j=1;j<=n;j++)
        		a[i][j] = b[i][j];
	}
    int cnt = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (a[i][j] == '@')
                cnt++;
    cout << cnt << "\n";
    return 0;
}

另一种滚动形式

#include <bits/stdc++.h>
using namespace std;
int n, m;
// [天数][行][列]
char a[2][105][105];
int now,last;//当前天、前一天 
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    now = 1;
    last = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            cin >> a[now][i][j];
    cin >> m;
    last = now;
    now = 1-last;
    for (int day = 2; day <= m; day++)
    {
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
            {
                if (a[last][i][j] == '#')
                    a[now][i][j] = '#';
                else if (a[last][i - 1][j] == '@' ||
                         a[last][i][j - 1] == '@' || 
						 a[last][i][j] == '@' || 
						 a[last][i][j + 1] == '@' ||
                         a[last][i + 1][j] == '@')
                    a[now][i][j] = '@';
            }
	    last = now;
	    now = 1-last;
	}
    int cnt = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (a[last][i][j] == '@')
                cnt++;
    cout << cnt << "\n";
    return 0;
}

二维数组直接记录每个位置哪天被传染

#include <bits/stdc++.h>
using namespace std;
int n;
// g[i][j] 表示 第 day 天，(i,j) 的状态
// -1: 墙
// 0: 健康人
// x: 第 x 天被传染的人
int g[105][105];
int m;
int main()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
        {
            char c;
            cin >> c;
            if (c == '#')
                g[i][j] = -1;
            else if (c == '.')
                g[i][j] = 0;
            else if (c == '@')
                g[i][j] = 1;
        }
    cin >> m;
    for (int day = 2; day <= m; day++)
    {
        // 把 g 数组变成下一天的情况
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= n; j++)
            {
                if (g[i][j] == 0)
                {
                    if (g[i - 1][j] == day - 1 ||
                        g[i + 1][j] == day - 1 ||
                        g[i][j - 1] == day - 1 ||
                        g[i][j + 1] == day - 1)
                    {
                        // g[i][j] 周边有昨天被传染的，今天就被传染了
                        g[i][j] = day;
                    }
                }
            }
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (g[i][j] > 0)
                ans++;
    cout << ans;
    return 0;
}