AOJ673 聪明的输入法(字典树)

#include<cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define num(x) x-'a';
#define MAX 1000000
struct Trie{
    int next[26];
    int count;
    int prefix;//记录以此为前缀串的数量
}tree[MAX];
char suffix[15];//后缀
int f,length;
int dfs(int depth,int node){//查找出现次数最多的串，返回以此出发串出现频率最大值
    int best=0,sel;
    if(tree[node].count&&(tree[node].count>f)){
        f=tree[node].count;
        length=depth;
        best=f;
    }
    for(int i=0;i<26;i++){
            int j=tree[node].next[i];
        if(j&&tree[j].prefix>f){//摆脱TLE的重要剪枝
            int t=dfs(depth+1,tree[node].next[i]);
            if(best<t){
               best=t;
               sel=i;
            }
        }
    }
    if(best==f){
        suffix[depth]=(char)(sel+'a');
    }
    return best;
}
int insert(char *s){
    int len=strlen(s),node=0;
    static int next=0;
    if(next==0){
        memset(&tree[0],0,sizeof(Trie));
    }
    for(int i=0;i<len;i++){
            int c=num(s[i]);
        if(!tree[node].next[c]){
            memset(&tree[++next],0,sizeof(Trie));
            tree[node].next[c]=next;
        }
        node=tree[node].next[c];
        tree[node].prefix++;
    }
    return ++tree[node].count;
}
void search(char *s){
    int node=0,len=strlen(s);
    for(int i=0;i<len;i++){
        int c=num(s[i]);
        if(!tree[node].next[c]){
            printf("%s\n",s);
            return;
        }
        node=tree[node].next[c];
    }
    printf("%s",s);
    length=f=0;
    dfs(0,node);//深搜找后缀
    for(int i=0;i<length;i++){
        printf("%c",suffix[i]);
    }
    printf("\n");
}
int main(){
    int t;
    char str[12];
    scanf("%d",&t);
    while(t--){
        scanf("%s",str);
        search(str);
        insert(str);
    }
    return 0;
}