UVA 11488 Hyper Prefix Sets 字典树

题意：给你一个01串集合 定义P(S)为S集合字符串的公共前缀长度与S中字符串个数的乘积 要你从中选一个S 使得P(S)最大

思路：又是裸的字典树。。。感觉做水题真爽。。。十分钟一个。。。用字典树存下每个字符串的信息（重复次数和深度）边存入边更新即可

#include <cstdio>
#include <cstring>
using namespace std;

#define REP( i, a, b ) for( int i = a; i < b; i++ )

const int maxn = 50000 + 10;

struct Trie{
          int va, deep;
          Trie *next[2];
          Trie(int va = 0, int deep = 0) : va(va), deep(deep) { next[0] = next[1] = NULL; }
};

int n;

int Max(int a, int b){ return a > b ? a : b; }

int CreatTrie(Trie *root, char *str){
          int ans = 0;
          int len = strlen(str);
          Trie *p = root, *q;
          REP(i, 0, len){
                    int id = str[i] - '0';
                    if(p -> next[id] == NULL){
                              q = new Trie(1, i + 1);
                              p -> next[id] = q;
                              ans = Max(ans, p -> next[id] -> va * p -> next[id] -> deep);
                              p = p -> next[id];
                    }
                    else{
                              p -> next[id] -> va ++;
                              ans = Max(ans, p -> next[id] -> va * p -> next[id] -> deep);
                              p = p -> next[id];
                    }
          }
          return ans;

}

void DelTrie(Trie *root){
          if(root == NULL) return;
          DelTrie(root -> next[0]);
          DelTrie(root -> next[1]);
          delete[] root;
}

void solve(){
          int ans = 0;
          char str[210];
          Trie *root = new Trie(0, 0);
          scanf("%d", &n);
          REP(i, 0, n){
                    scanf("%s", str);
                    ans = Max(CreatTrie(root, str), ans);
          }
          printf("%d\n", ans);
          DelTrie(root);
}


int main()
{
          //freopen("in.txt", "r", stdin);
          int T;
          scanf("%d", &T);
          while(T--) solve();
          return 0;
}