Codeforces 667C Reberland Linguistics 记忆化搜索

链接

题意

思路

代码

#include <iostream>
#include <cstdio>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <string>

#define LL long long
#define INF 0x3f3f3f3f
#define eps 1e-8
#define MAXN 10005
using namespace std;

string s, ss;
int len;
vector<string> res;
map<string, bool> mp;
map<pair<string, int>, bool> vis;
int f[MAXN];
void dfs(int pos, string last){
if (vis[make_pair(last, pos)] == true) return;
int cur = -1;
if (pos >= len) return;
for (int i = 0; i < 2; ++i){
if (pos + 2  + i<= len){
string temp = s.substr(pos, 2 + i);
if (!mp[temp]){
res.push_back(temp);
mp[temp] = true;
}
if (temp != last){
dfs(pos + 2 + i, temp);
}
}
}
vis[make_pair(last,pos)] = true;
}

int main(){
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif // ONLINE_JUDGE
cin >> ss;
ss = ss.substr(5);
len = ss.length();
for (int i = len - 1; i >= 0; --i){
s.push_back(ss[i]);
}
dfs(0, "");
int ans = res.size();
printf("%d\n", ans);
for (int i = 0; i < res.size(); ++i){
int len = res[i].length();
for (int j = 0; j < (len >> 1); ++j){
swap(res[i][j], res[i][len - j - 1]);
}
}
sort(res.begin(), res.end());
for (int i = 0; i < res.size(); ++i){
cout << res[i] << endl;
}
}