HDU 1247 Hat’s Words（字典树）

来源：互联网发布：家用中央空调知乎编辑：程序博客网时间：2024/06/18 16:52

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1247

题意：输入一些单词，输出这些单词中可以由其他2个单词构成的单词。

思路：暴力+字典树

代码

#include <iostream>#include <stdio.h>#include <string.h>#include <math.h>#include <algorithm>#include <string>#include <vector>using namespace std;#define lson l, m, rt << 1#define rson m + 1, r, rt << 1 | 1#define ceil(x, y) (((x) + (y) - 1) / (y))const int SIZE = 30;const int N = 5e4 + 10;const int INF = 0x7f7f7f7f;struct Trie {int val[SIZE];bool e;};int sz;Trie pn[N];string str[N];string ans[N];int newnode() {memset(pn[sz].val, 0, sizeof(pn[sz].val));return sz++;}void init() {sz = 0;newnode();}void insert(string s) {int u = 0;for (int i = 0; i < s.size(); i++) {int idx = s[i] - 'a';if (!pn[u].val[idx]) {pn[u].val[idx] = newnode();pn[pn[u].val[idx]].e = false;}u = pn[u].val[idx];}pn[u].e = true;}bool findpre(string s, int st, int ed) {int u = 0;for (int i = st; i <= ed; i++) {int idx = s[i] - 'a';if (!pn[u].val[idx])return false;u = pn[u].val[idx];}if (pn[u].e)return true;return false;}int main() {int n = 0;while (cin >> str[n]) {insert(str[n++]);}int k = 0;for (int i = 0; i < n; i++) {for (int j = 0; j < str[i].size() - 1; j++)if (findpre(str[i], 0, j) && findpre(str[i], j + 1, str[i].size() - 1)) {ans[k++] = str[i];break;}}sort(ans, ans + k);for (int i = 0; i < k; i++)cout << ans[i] << endl;return 0;}

0 0