谁能帮我解释下这段代码

[yangboufo]

是采用暴搜的方法，关于四色图问题，能详细的解释下吗？

#include<iostream>

using namespace std;

int colour[40],cnt,n;

int map[100][100];

int judge(int deep,int k)
{
for( int j = 0; j < n;j++)
if(map[deep][j] && colour[j] == k)
return 0;
return 1;
}

int solve(int deep , int k )
{
if(deep == n )
return 1;
else
{
for( int i = 0 ;i < k;i++)
{
if( judge(deep,i) )
{
colour[deep] = i;
if(solve(deep + 1 , k))
return 1;
}
}
}
return 0;
}
int main()
{
while(cin>>n && n)
{
cnt = 0;
char a[100][100];

memset(map,0,sizeof(map));

memset(a,0,sizeof(a));

memset(colour,-1,sizeof(colour));

int i , j ;

for(i = 0 ;i < n ;i++)
{
cin>>a[i];
}
for(i = 0 ; i < n ;i++)
{
for( j = 2 ; j < n + 2;j++)
{
if(a[i][j] == '\0') break;

map[i][int(a[i][j] - 'A')] = 1;

map[int(a[i][j] - 'A')][i] = 1;
}//生成邻接矩阵
}
if( solve(0,1) )
{cout<<"1 channel needed."<<endl;continue;}
else if( solve(0,2))
{cout<<"2 channels needed."<<endl;continue;}
else if(solve(0,3))
{cout<<"3 channels needed."<<endl;continue;}
else
cout<<"4 channels needed."<<endl;


}
return 0;
}