题目：
我是超链接
题解：
普及STL用法+string系列
代码：
#include <cstdio> #include <string> #include <queue> #include <iostream> #include <set> #include <vector> using namespace std; struct node{int num; string a; node(int num,string a):num(num),a(a){}}; vector< pair<string,string> > v; set <string> repe; //map <string,int> repe; string A,B; bool bfs() { queue<node>q; q.push(node(0,A)); while (!q.empty()) { node now=q.front(); q.pop(); if (now.num>10) return 0; for (int i=0;i<v.size();i++) if (now.a.find(v[i].first)!=-1) for (int j=now.a.find(v[i].first);j<now.a.length();j=now.a.find(v[i].first,j+1)) //这个串里有子串（不知几个），一次一次往下找 { string t=now.a; t.replace(j,v[i].first.length(),v[i].second); if (t==B) {printf("%d",now.num+1);return 1;} if (!repe.count(t)) { q.push(node(now.num+1,t)); repe.insert(t); } } } return 0; } int main() { cin>>A>>B; string a,b; while (cin>>a>>b) v.push_back(make_pair(a,b)); if (!bfs()) printf("NO ANSWER!"); }
