poj 1129 DFS 无剪枝就可AC

#include <iostream>
#include <string>

using namespace std;

int rep[26][27],channelChosen[26];

bool check(int curRep,int curCha,int amount)
{
for (int j = 1;j <= rep[curRep][0];j++)
{
if(channelChosen[curRep]==channelChosen[rep[curRep][j]-1])
return false;
}
return true;
}

int DFS(int curRepeater,int curChannel,int num)
{
if(curRepeater>=num)
return curChannel;
for (int i = 1;i <= curChannel;i++)
{
channelChosen[curRepeater]=i;
if(check(curRepeater,curChannel,num))
{
return DFS(curRepeater+1,curChannel,num);
}
else
continue;
}
channelChosen[curRepeater]=curChannel+1;
return DFS(curRepeater+1,curChannel+1,num);
}

int main()
{
int numOfRepeaters;
while (cin>>numOfRepeaters&&numOfRepeaters!=0)
{
string str;
for (int i = 0;i < numOfRepeaters;i++)
{
cin>>str;
int j = 1;
string::iterator it = str.begin()+2;
for (;it != str.end();it++)
{
rep[i][j++] = *it-'A'+1;
}
rep[i][0] = j-1;
}
int result = DFS(0,1,numOfRepeaters);
string res = (result==1)?" channel needed.":" channels needed.";
cout<<result<<res<<endl;
}
}