参照LeetCode 695. 岛屿的最大面积思路，采用DFS方法，对看台观众进行遍历，求最大的球迷群体的人的个数时，顺便求球迷群体的群体个数
代码示例：
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int dfs(vector<vector<int>>&grid, int n, int m, int i, int j)
{
int sum = 1;
grid[i][j] = 0;
int dir[8][2] = { { -1,0 },{ 1,0 },{ 0,-1 },{ 0,1 },{ -1,-1 },{ 1,-1 },{ -1,1 },{ 1,1 } };
for (int num = 0; num < 8; num++)
{
int x = dir[num][0];
int y = dir[num][1];
if (x >= 0 && x < n&&y >= 0 && y < m&&grid[x][y])
sum+=dfs(grid, n, m, x, y);
}
return sum;
}
void MaxOfGroup(vector<vector<int>>&grid, int n, int m)
{
int Max = 0;//最大的球队群体
int count=0;//群体个数
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
{
if (grid[i][j] == 1)
{
Max = max(Max, dfs(grid, n, m, i, j));
count++;
}
}
cout << count << ',' << Max;
}
int main()
{
int n, m;
char c;
cin >> n >> c >> m;
vector<int>temp;
vector<vector<int>>grid;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m - 1; j++)
{
cin >> grid[i][j];
cin >> c;
}
cin >> grid[i][m - 1];
}
MaxOfGroup(grid, n, m);
return 0;
}