#include <stdio.h>#include <string.h>#define MAX_D 1024#define HASH_SIZE 65536struct node { struct node *next; int val, cnt;};int B, L, D;int map[256], ans[256], best;char dict[MAX_D][16];struct node nodes[MAX_D], *hash[HASH_SIZE];int nodes_cnt;int vis[HASH_SIZE], tm;inline void calc(){ int i, h, val, uni; char *s; struct node *t; tm++; nodes_cnt = 0; for (i = 0; i < D; i++) { val = 0; for (s = dict[i]; *s; s++) val = val*31 + map[*s] + 'a'; h = val & (HASH_SIZE - 1); if (vis[h] != tm) { vis[h] = tm; hash[h] = NULL; } for (t = hash[h]; t; t = t->next) if (t->val == val) break; if (!t) { t = &nodes[nodes_cnt++]; t->val = val; t->cnt = 0; t->next = hash[h]; hash[h] = t; } t->cnt++; } uni = 0; for (i = 0; i < nodes_cnt; i++) if (nodes[i].cnt == 1) uni++; if (uni > best) { best = uni; memcpy(ans, map, sizeof(map)); }}void dfs(int b, int l){ int i, cnt; cnt = L - l - (B - b) + 1; for (i = 0; i < cnt; i++) map[l + 'A' + i] = b; if (b == B - 1) { calc(); return ; } for (i = cnt; i >= 1; i--) dfs(b + 1, l + i);}int main(){ int i; scanf("%d%d%d", &B, &L, &D); for (i = 0; i < D; i++) scanf("%s", dict[i]); dfs(0, 0); printf("%dn", best); for (i = 'A'; i < 'A' + L; i++) { if (ans[i] != ans[i - 1]) putchar('n'); putchar(i); } putchar('n'); return 0;}
