codevs上面的單詞接龍...
腦殘了..唉..題解放這屯着..
記一下這個函數..
<string>裏面
substr(0,p)
複製子字符串,要求從指定位置開始,並具有指定的長度
#include<iostream>
#include<string>
#define MAXN 21
using namespace std;
int n;
string words[MAXN];
int count_used[MAXN];
string max_str="";
void input()
{
cin>>n;
int i;
for(i=1;i<=n;i++)
{
cin>>words[i];
count_used[i]=0;
}
cin>>words[0];
}
string dragon(string str_pre,string str_lat)
{
int min_len=str_pre.length()>str_lat.length()?str_lat.length():str_pre.length();
if(str_pre.length()==1){min_len++;}
int p;
for(p=1;p<min_len;p++)
{
if(str_pre.substr(str_pre.length()-p,p)==str_lat.substr(0,p))
{string str_connected=str_pre+str_lat.substr(p);
if(str_connected.length()>max_str.length())
{
max_str=str_connected;}
return str_connected;}
}
return "";
}
void dfs(string cur_word)
{
int i;
for(i=1;i<=n;i++)
{
if(count_used[i]>1)
{continue;}
string str_connected=dragon(cur_word,words[i]);
if(str_connected.length()==0){continue;}
count_used[i]++;
dfs(str_connected);
count_used[i]--;
}
}
int main()
{
input();
dfs(words[0]);
cout<<max_str.length();
return 0;
}