CSU 1457 Boggle （字典树+DFS）

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题目链接：http://acm.csu.edu.cn/csuoj/problemset/problem?pid=1457

读了一遍题想到了字典树，但不知道怎么写，队友一个单词一个单词的枚举，然后暴搜过了，赛后查题解发现就是字典树+暴搜，比队友写的少了几百毫秒

#include <bits/stdc++.h>
using namespace std;
int trie_n;
const int MAXN = 400006;
char mat[5][5];
bool vis[5][5],book[MAXN];
int to[8][2] = {{0,1},{1,0},{0,-1},{-1,0},{1,1},{1,-1},{-1,-1},{-1,1}};
int point[] = {0,0,0,1,1,2,3,5,11,11,11};
struct Trie_node
{
    int next[26];
    int index,val;
    Trie_node()
    {
        index = val = -1;
        fill(next,next + 26,-1);
    }
};
char temp[10];
Trie_node trie[MAXN];
int ans1,ans2;
char word[15];
void trie_insert(char s[],int index)
{
    int root = 0;
    int len = strlen(s);
    for(int i = 0; i < len; i++) {
        int next = trie[root].next[s[i] - 'A'];
        if(next == -1) {
            next = trie[root].next[s[i] - 'A'] = trie_n++;
        }
        root = next;
    }
    trie[root].index = index;
    trie[root].val = point[len];
}
void solve(char *s)
{
    int root = 0;
    int len = strlen(s);
    for(int i = 0; i < len; i++) {
        int next = trie[root].next[s[i] - 'A'];
        if(next == -1) break;
        root = next;
    }
    if(trie[root].val != -1 && !book[trie[root].index]) {
        book[trie[root].index] = 1;
        ans1++;
        ans2 += trie[root].val;
        if(ans1 == 1) memcpy(word,s,10);
        else if(len == strlen(word) && strcmp(s,word) < 0)
            memcpy(word,s,10);
        else if(len > strlen(word))
            memcpy(word,s,10);
    }
}
void dfs(int x,int y,int cur)
{
    if(cur > 8) return;
    temp[cur - 1] = mat[x][y];
    temp[cur] = '\0';
    solve(temp);
    vis[x][y] = 1;
    for(int i = 0; i < 8; i++) {
        int tx = x + to[i][0];
        int ty = y + to[i][1];
        if(tx < 0 || ty < 0 || tx >= 4 || ty >= 4) continue;
        if(vis[tx][ty]) continue;
        vis[tx][ty] = 1;
        dfs(tx,ty,cur + 1);
        vis[tx][ty] = 0;
    }
    vis[x][y] = 0;
}
int main(void)
{
    int n;
    char str[20];
    scanf("%d",&n);
    trie_n = 1;
    for(int i = 1; i <= n; i++) {
        scanf("%s",str);
        trie_insert(str,i);
    }
    int q;
    scanf("%d",&q);
    while(q--) {
        ans1 = ans2 = 0;
        memset(book,false,sizeof(book));
        for(int i = 0; i < 4; i++) scanf("%s",mat[i]);
        for(int i = 0; i < 4; i++) {
            for(int j = 0; j < 4; j++) {
                dfs(i,j,1);
            }
        }
        printf("%d %s %d\n",ans2,word,ans1);
    }
    return 0;
}