LA 4126 Password Suspects

  1 #include <algorithm>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <string>
  5 #include <queue>
  6 #include <map>
  7 #include <set>
  8 #include <ctime>
  9 #include <cmath>
 10 #include <iostream>
 11 #include <assert.h>
 12 #define pi acos(-1.)
 13 using namespace std;
 14 typedef long long ll;
 15 const int int_inf = 0x3f3f3f3f;
 16 const ll ll_inf = 1ll << 62;
 17 const int INT_INF = (int)((1ll << 31) - 1);
 18 const int mod = 1e6 + 7;
 19 const double double_inf = 1e30;
 20 typedef unsigned long long ul;
 21 #pragma comment(linker, "/STACK:102400000,102400000")
 22 #define max(a, b) ((a) > (b) ? (a) : (b))
 23 #define min(a, b) ((a) < (b) ? (a) : (b))
 24 #define mp make_pair
 25 #define st first
 26 #define nd second
 27 #define keyn (root->ch[1]->ch[0])
 28 #define lson (u << 1)
 29 #define rson (u << 1 | 1)
 30 #define pii pair<int, int>
 31 #define pll pair<ll, ll>
 32 #define pb push_back
 33 #define type(x) __typeof(x.begin())
 34 #define foreach(i, j) for(type(j)i = j.begin(); i != j.end(); i++)
 35 #define FOR(i, s, t) for(int i = (s); i <= (t); i++)
 36 #define ROF(i, t, s) for(int i = (t); i >= (s); i--)
 37 #define dbg(x) cout << x << endl
 38 #define dbg2(x, y) cout << x << " " << y << endl
 39 #define clr(x, i) memset(x, (i), sizeof(x))
 40 #define maximize(x, y) x = max((x), (y))
 41 #define minimize(x, y) x = min((x), (y))
 42 #define low_bit(x) ((x) & (-x))
 43 
 44 inline int readint(){
 45     int x;
 46     scanf("%d", &x);
 47     return x;
 48 }
 49 
 50 inline int readstr(char *s){
 51     scanf("%s", s);
 52     return strlen(s);
 53 }
 54 
 55 class cmpt{
 56 public:
 57     bool operator () (const int &x, const int &y) const{
 58         return x > y;
 59     }
 60 };
 61 
 62 int Rand(int x, int o){
 63     //if o set, return [1, x], else return [0, x - 1]
 64     if(!x) return 0;
 65     int tem = (int)((double)rand() / RAND_MAX * x) % x;
 66     return o ? tem + 1 : tem;
 67 }
 68 
 69 void data_gen(){
 70     srand(time(0));
 71     freopen("in.txt", "w", stdout);
 72     int times = 10;
 73     printf("%d\n", times);
 74     while(times--){
 75         int n = Rand(500, 1), m = Rand(500, 1);
 76         printf("%d %d\n", n, m);
 77         FOR(i, 1, n){
 78             FOR(j, 1, m) printf("%c", Rand(2, 0) + ‘a‘);
 79             putchar(‘\n‘);
 80         }
 81         n = Rand(min(10, n), 1), m = Rand(min(10, m), 1);
 82         printf("%d %d\n", n, m);
 83         FOR(i, 1, n){
 84             FOR(j, 1, m) printf("%c", Rand(2, 0) + ‘a‘);
 85             putchar(‘\n‘);
 86         }
 87     }
 88 }
 89 
 90 struct cmpx{
 91     bool operator () (int x, int y) { return x > y; }
 92 };
 93 int debug = 0;
 94 int dx[] = {-1, 1, 0, 0};
 95 int dy[] = {0, 0, -1, 1};
 96 //-------------------------------------------------------------------------
 97 const int maxn = 12;
 98 const int sigma_size = 26;
 99 ll dp[30][1 << 12][maxn * maxn];
100 int nex[maxn * maxn][sigma_size];
101 int state[maxn * maxn];
102 int info[maxn * maxn];
103 int tot;
104 map<string, int> mapi;
105 struct Trie{
106     int ch[maxn * maxn][sigma_size];
107     int idx(char c) { return c - ‘a‘; }
108     int sz;
109     void init() { clr(ch[0], 0); sz = 0; clr(info, 0); }
110     void insert(char *s){
111         int u = 0;
112         while(*s){
113             int v = ch[u][idx(*s)];
114             if(!v) { ch[u][idx(*s)] = v = ++sz; clr(ch[sz], 0); }
115             u = v;
116             ++s;
117         }
118         if(!info[u]) info[u] = ++tot;
119     }
120 
121     char tem[20];
122     int k;
123 
124     void dfs1(int u){
125         FOR(i, 0, sigma_size - 1){
126             int v = ch[u][i];
127             if(!v) continue;
128             tem[k++] = i + ‘a‘, tem[k] = ‘\0‘;
129             mapi[string(tem)] = v;
130             dfs1(v);
131             --k;
132         }
133     }
134 
135     void dfs2(int u){
136         FOR(i, 0, sigma_size - 1){
137             int v = ch[u][i];
138             if(!v) continue;
139             tem[k++] = i + ‘a‘, tem[k] = ‘\0‘;
140             FOR(j, 0, k - 1){
141                 string str = string(tem + j);
142                 if(mapi.find(str) != mapi.end() && info[mapi[str]]) state[v] |= 1 << (info[mapi[str]] - 1);
143             }
144             FOR(j, 0, sigma_size - 1){
145                 tem[k++] = j + ‘a‘, tem[k] = ‘\0‘;
146                 int ok = 0;
147                 FOR(z, 0, k - 1){
148                     string str = string(tem + z);
149                     if(mapi.find(str) != mapi.end()){
150                         nex[v][j] = mapi[str];
151                         ok = 1;
152                         break;
153                     }
154                 }
155                 if(!ok) nex[v][j] = 0;
156                 --k;
157             }
158             dfs2(v);
159             --k;
160         }
161     }
162     int S;
163     void getNext(){
164         mapi.clear();
165         k = 0, dfs1(0);
166         k = 0, clr(state, 0), dfs2(0);
167         FOR(i, 0, sigma_size - 1) nex[0][i] = ch[0][i];
168     }
169 }trie;
170 
171 ll power(ll a, ll p){
172     ll ans = 1;
173     while(p){
174         if(p & 1) ans *= a;
175         p >>= 1ll;
176         a = a * a;
177     }
178     return ans;
179 }
180 int n, m;
181 char mt[maxn][maxn];
182 
183 ll dfs(int u, int S, int l){
184     if(dp[u][S][l] != -1) return dp[u][S][l];
185     if(u == n) return dp[u][S][l] = S == ((1 << tot) - 1);
186     if(S == (1 << tot) - 1) return dp[u][S][l] = power(26, n - u);
187     ll tem = 0;
188     FOR(i, 0, sigma_size - 1){
189         int next_pointer = nex[l][i];
190         int next_S = S | state[next_pointer];
191         tem += dfs(u + 1, next_S, next_pointer);
192     }
193     return dp[u][S][l] = tem;
194 }
195 
196 char buf[maxn << 2];
197 int k;
198 
199 void printAns(int u, int S, int l){
200     if(!dp[u][S][l]) return;
201     if(u == n){
202         buf[k] = ‘\0‘;
203         puts(buf);
204         return;
205     }
206     FOR(i, 0, sigma_size - 1){
207         int next_pointer = nex[l][i];
208         int next_S = S | state[next_pointer];
209         buf[k++] = i + ‘a‘;
210         printAns(u + 1, next_S, next_pointer);
211         --k;
212     }
213 }
214 //-------------------------------------------------------------------------
215 
216 int main(){
217     //data_gen(); return 0;
218     //C(); return 0;
219     debug = 0;
220     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////
221     if(debug) freopen("in.txt", "r", stdin);
222     //freopen("out.txt", "w", stdout);
223     int kase = 0;
224     while(~scanf("%d%d", &n, &m) && n){
225         FOR(i, 0, m - 1) scanf("%s", mt[i]);
226         trie.init(), tot = 0;
227         FOR(i, 0, m - 1) trie.insert(mt[i]);
228         trie.getNext();
229         clr(dp, -1);
230         ll ans = dfs(0, 0, 0);
231         printf("Case %d: %lld suspects\n", ++kase, ans);
232         if(ans <= 42) k = 0, printAns(0, 0, 0);
233     }
234     //////////////////////////////////////////////////////////////////////////////////////////////////////////////
235     return 0;
236 }