lightoj 1224

很简单的Trie树，记录每个前缀的次数，dfs一次Trie即可

#include<set>
#include<map>
#include<list>
#include<stack>
#include<queue>
#include<cmath>
#include<ctime>
#include<cstdio>
#include<string>
#include<vector>
#include<cstring>
#include<cstdlib>
#include<sstream>
#include<iostream>
#include<algorithm>
using namespace std;
#define LL long long
#define INF 0x7fffffff
#define debug cout << "here" << endl
#define CLR(X, Y) memset(X, Y sizeof Y)
#define FOR(X, Y) for(int i = X;i < Y;i ++)
inline int myMin(int x, int y){return x < y ? x : y;}
inline int myMax(int x, int y){return x < y ? y : x;}
struct Node{
    int cnt;
    Node* child[4];
    Node(){
        cnt = 0;
        for(int i = 0;i < 4;i ++) child[i] = NULL;
    }
};
int ans;
Node *root;
int Hash(char c){
    if(c == 'A') return 0;
    if(c == 'G') return 1;
    if(c == 'C') return 2;
    if(c == 'T') return 3;
}

void insert(char* str){
    Node *tmp = root;
    while(str[0]){
        int idx = Hash(str[0]);
        if(tmp->child[idx] == NULL) tmp->child[idx] = new Node();
        tmp = tmp->child[idx];
        tmp->cnt ++;
        str++;
    }
}

void dfs(int dep, Node *tmp){
    if(dep*tmp->cnt > ans) ans = dep*tmp->cnt;
    for(int i = 0;i < 4;i ++){
        if(tmp->child[i]) dfs(dep+1, tmp->child[i]);
    }
}

int main(int argc, char* argv[]){
    char str[55];
    int t, n, CASE(0);
   // freopen("in.cpp", "r", stdin);
    scanf("%d", &t);
    while(t--){
        root = new Node();
        scanf("%d", &n);
        for(int i = 0;i < n;i ++){
            scanf("%s", str);
            insert(str);
        }
        ans = 0;
        dfs(0, root);
        printf("Case %d: %d\n", ++CASE, ans);
    }
    return 0;
}

树即可，