【POJ】1204 Word Puzzles

这道题目各种wa。首先是错了一个坐标，居然没测出来。然后是剪枝错误。搜索pen时就返回，可能还存在串pen*。

#include <cstdio>
#include <cstring>
#include <cstdlib>

#define MAXN 1005

typedef struct Trie {
    int v;
    Trie *next[26];
    Trie() {
        v = 0;
        for (int i=0; i<26; ++i)
            next[i] = NULL;
    }
} Trie;

Trie root;
int direct[8][2] = {{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1}};
char map[MAXN][MAXN], buf[MAXN];
int ans[MAXN][3], n, m, xx, yy;
bool visit[MAXN];

void create(char str[], int in) {
    int i = 0, id;
    Trie *p = &root, *q;

    while (str[i]) {
        id = str[i] - 'A';
        ++i;
        if (p->next[id] == NULL) {
            q = new Trie();
            p->next[id] = q;
        }
        p = p->next[id];
    }
    p->v = in;
}

void find(Trie *t, int x, int y, int k) {
    if (t == NULL)
        return ;

    if (t->v && !visit[t->v]) {
        visit[t->v] = true;
        ans[t->v][0] = xx;
        ans[t->v][1] = yy;
        ans[t->v][2] = k;
    }
    if (x<0 || x>=n || y<0 || y>=m)
        return ;
    find(t->next[map[x][y]-'A'], x+direct[k][0], y+direct[k][1], k);
}

void search() {
    int k;

    memset(visit, false, sizeof(visit));

    for (xx=0; xx<n; ++xx)
        for (yy=0; yy<m; ++yy)
            for (k=0; k<8; ++k)
                find(&root, xx, yy, k);
}

int main() {
    int w;
    int i;

    scanf("%d%d%d",&n,&m,&w);

    for (i=0; i<n; ++i)
        scanf("%s", map[i]);

    for (i=1; i<=w; ++i) {
        scanf("%s", buf);
        create(buf, i);
    }
    search();
    for (i=1; i<=w; ++i)
        printf("%d %d %c
", ans[i][0], ans[i][1], ans[i][2]+'A');

    return 0;
}