UVA 11488 Hyper Prefix Sets (Trie)
2017-06-12 08:58 tlnshuju 阅读(191) 评论(0) 编辑 收藏 举报http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=2483
Hyper Prefix Sets
Prefix goodness of a set string islength of longest common prefix*number of strings in the set.For example the prefix goodness of theset {000,001,0011} is 6.You are given a set of binarystrings. Find the maximum prefixgoodness among all possible subsets of these binary strings.
Input
First line of the input contains T(≤20)the number of test cases. Each of the test cases start withn(≤50000) the number of strings. Eachof the next n lines contains a string containing only 0 andMaximum length of each of thesestring is 200.
Output
For each test case output the maximumprefix goodness among all possible subsets of n binarystrings.
Sample Input
4
4
0000
0001
10101
010
2
01010010101010101010
11010010101010101010
3
010101010101000010001010
010101010101000010001000
010101010101000010001010
5
01010101010100001010010010100101
01010101010100001010011010101010
00001010101010110101
0001010101011010101
00010101010101001
Output for Sample Input
6
20
66
44
Problem Setter : Abdullah Al Mahmud
Special Thanks : Manzurur Rahman Khan
题意:
给出N个字符串,要求选出若干个,使得选中的字符串的公共前缀长度与选中字符串的个数的乘积最大。
分析:
简单粗暴的Trie模板题。
对于Tire中的每个结点加入两个信息:该结点的深度及该结点杯訪问的次数。最后求出这两个信息的最大值即可了,边加入字符串边维护即可。
/* * * Author : fcbruce * * Time : Sat 04 Oct 2014 09:17:50 PM CST * */ #include <cstdio> #include <iostream> #include <sstream> #include <cstdlib> #include <algorithm> #include <ctime> #include <cctype> #include <cmath> #include <string> #include <cstring> #include <stack> #include <queue> #include <list> #include <vector> #include <map> #include <set> #define sqr(x) ((x)*(x)) #define LL long long #define itn int #define INF 0x3f3f3f3f #define PI 3.1415926535897932384626 #define eps 1e-10 #ifdef _WIN32 #define lld "%I64d" #else #define lld "%lld" #endif #define maxm 2 #define maxn 5000007 using namespace std; struct Trie { int ch[maxn][maxm]; int deep[maxn]; int cnt[maxn][maxm]; int MAX; int sz; Trie() { sz=1; deep[0]=0; MAX=0; memset(cnt[0],0,sizeof cnt[0]); memset(ch[0],0,sizeof ch[0]); } void clear() { sz=1; deep[0]=0; MAX=0; memset(cnt[0],0,sizeof cnt[0]); memset(ch[0],0,sizeof ch[0]); } int idx(const char ch) { return ch-'0'; } void insert(const char *s) { for (int i=0,j=0;s[i]!='\0';i++) { int c=idx(s[i]); if (ch[j][c]==0) { memset(ch[sz],0,sizeof ch[sz]); memset(cnt[sz],0,sizeof cnt[sz]); deep[sz]=i+1; ch[j][c]=sz++; } j=ch[j][c]; cnt[j][c]++; MAX=max(MAX,deep[j]*cnt[j][c]); } } }trie; char str[233]; int main() { #ifdef FCBRUCE freopen("/home/fcbruce/code/t","r",stdin); #endif // FCBRUCE int T_T; scanf("%d",&T_T); while (T_T--) { trie.clear(); int n; scanf("%d",&n); for (int i=0;i<n;i++) { scanf("%s",str); trie.insert(str); } printf("%d\n",trie.MAX); } return 0; }