UVA 11488 字典树

题意：

题目链接：https://vjudge.net/problem/UVA-11488
给出n个串，找出一个串的集合，使得集合中所有串的最长公共前缀与集合元素的个数的乘积最大。

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思路：

字典树简单应用

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代码：

#include <bits/stdc++.h>using namespace std;typedef long long LL;const int MAXN = 5e4 + 10;struct node {    node *Next[2];    LL cnt;};LL ans;struct Trie {    node *root;    void init() {        root = new node;        root->Next[0] = root->Next[1] = NULL;    }    void insert(char *str) {        node *p = root;        int len = strlen(str);        for (int i = 0; i < len; i++) {            int id = str[i] - '0';            if (p->Next[id] == NULL) {                node *q = new node;                for (int j = 0; j < 2; j++) q->Next[j] = NULL;                p->Next[id] = q;                p = p->Next[id];                p->cnt = 1;            }            else {                p = p->Next[id];                p->cnt++;            }        }    }    void erase(node *p) {        for (int i = 0; i < 2; i++) {            if (p->Next[i] == NULL) continue;            erase(p->Next[i]);        }        delete p;    }    void dfs(node *p, int dep) {        ans = max(ans, dep * (p->cnt));        for (int i = 0; i < 2; i++) {            if (p->Next[i] == NULL) continue;            dfs(p->Next[i], dep + 1);        }    }} trie;char str[MAXN];int main() {    //freopen("in.txt", "r", stdin);    int T;    scanf("%d", &T);    while (T--) {        int n;        scanf("%d", &n);        trie.init();        for (int i = 0; i < n; i++) {            scanf("%s", str);            trie.insert(str);        }        ans = 0;        trie.dfs(trie.root, 0);        printf("%lld\n", ans);        trie.erase(trie.root);    }    return 0;}