UVa10391 Compound Words

想了半天, 总是绕不开那个该死的O(N²).

看了看题解, 发现直接枚举每个单词的子串就ok了...

对啊..毕竟最长的单词

Pneumonoultramicroscopicsilicovolcanoconiosis(肺尘病)

也不过45个字母嘛...

所以啊, 想不出来的时候,可以考虑从相反的方向思考

#include <cstdio>
#include <cstring>
#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
const int MAXN = 120000 + 20;

string str[MAXN];
set<string> S;
vector<string> ans;

int main()
{
    ios::sync_with_stdio(false);
    int cnt = 0;
    while(cin>>str[++cnt]) S.insert(str[cnt]);

    string tmp1, tmp2;
    for(int i = 1; i <= cnt; i++)
        for(int j = 1; j < (int) str[i].size() - 1; j++)
        {
            tmp1 = str[i].substr(0, j),
            tmp2 = str[i].substr(j, str[i].size() - j);

            if(S.find(tmp1) != S.end() && S.find(tmp2) != S.end()){
                ans.push_back(str[i]);
                break;
            }
        }

    sort(ans.begin(), ans.end());
    for(int i = 0; i < (int) ans.size(); i++)
        cout<<ans[i]<<endl;
    return 0;
}