POJ3294 Life Forms

Posted 2020-06-13

后缀数组。

  1 /* 3294 */
  2 #include <iostream>
  3 #include <sstream>
  4 #include <string>
  5 #include <map>
  6 #include <queue>
  7 #include <set>
  8 #include <stack>
  9 #include <vector>
 10 #include <deque>
 11 #include <algorithm>
 12 #include <cstdio>
 13 #include <cmath>
 14 #include <ctime>
 15 #include <cstring>
 16 #include <climits>
 17 #include <cctype>
 18 #include <cassert>
 19 #include <functional>
 20 #include <iterator>
 21 #include <iomanip>
 22 using namespace std;
 23 //#pragma comment(linker,"/STACK:102400000,1024000")
 24 
 25 #define sti                set<int>
 26 #define stpii            set<pair<int, int> >
 27 #define mpii            map<int,int>
 28 #define vi                vector<int>
 29 #define pii                pair<int,int>
 30 #define vpii            vector<pair<int,int> >
 31 #define rep(i, a, n)     for (int i=a;i<n;++i)
 32 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 33 #define clr                clear
 34 #define pb                 push_back
 35 #define mp                 make_pair
 36 #define fir                first
 37 #define sec                second
 38 #define all(x)             (x).begin(),(x).end()
 39 #define SZ(x)             ((int)(x).size())
 40 #define lson            l, mid, rt<<1
 41 #define rson            mid+1, r, rt<<1|1
 42 
 43 const int maxl = 1005;
 44 const int maxs = 105;
 45 const int maxn = maxl * maxs;
 46 char s[maxs][maxl];
 47 int id[maxn], pos[maxn], pn;
 48 bool visit[maxs];
 49 int a[maxn];
 50 int rank[maxn], height[maxn], sa[maxn];
 51 int wa[maxn], wb[maxn], wc[maxn], wv[maxn];
 52 int ns, ns_;
 53 
 54 bool cmp(int *r, int a, int b, int l) {
 55     return r[a]==r[b] && r[a+l]==r[b+l];
 56 }
 57 
 58 void da(int *r, int *sa, int n, int m) {
 59     int i, j, *x=wa, *y=wb, *t, p;
 60     
 61     for (i=0; i<m; ++i) wc[i] = 0;
 62     for (i=0; i<n; ++i) wc[x[i]=r[i]]++;
 63     for (i=1; i<m; ++i) wc[i] += wc[i-1];
 64     for (i=n-1; i>=0; --i) sa[--wc[x[i]]] = i;
 65     for (j=1,p=1; p<n; j*=2,m=p) {
 66         for (p=0,i=n-j; i<n; ++i) y[p++] = i;
 67         for (i=0; i<n; ++i) if (sa[i] >= j) y[p++] = sa[i]-j;
 68         for (i=0; i<n; ++i) wv[i] = x[y[i]];
 69         for (i=0; i<m; ++i) wc[i] = 0;
 70         for (i=0; i<n; ++i) wc[wv[i]]++;
 71         for (i=1; i<m; ++i) wc[i] += wc[i-1];
 72         for (i=n-1; i>=0; --i) sa[--wc[wv[i]]] = y[i];
 73         for (t=x,x=y,y=t, x[sa[0]]=0, p=1, i=1; i<n; ++i)
 74             x[sa[i]] = cmp(y, sa[i-1], sa[i], j) ? p-1:p++;
 75     }
 76 }
 77 
 78 void calheight(int *r, int *sa, int n) {
 79     int i, j, k = 0;
 80     
 81     for (i=1; i<=n; ++i) rank[sa[i]] = i;
 82     for (i=0; i<n; height[rank[i++]]=k)
 83     for (k?k--:0, j=sa[rank[i]-1]; r[j+k]==r[i+k]; ++k) ;
 84 }
 85 
 86 bool check(int b, int e) {
 87     int cnt = 0;
 88     
 89     memset(visit, false, sizeof(visit));
 90     rep(i, b, e+1) {
 91         if (!visit[id[sa[i]]]) {
 92             visit[id[sa[i]]] = true;
 93             ++cnt;
 94         }
 95     }
 96     
 97     return cnt > ns_;
 98 }
 99 
100 bool judge(int bound, int n) {
101     bool ret = false;
102     int b, e;
103     
104     b = e = 0;
105     rep(i, 1, n+1) {
106         if (height[i] >= bound) {
107             e = i;
108         } else {
109             if (check(b, e)) {
110                 if (!ret)
111                     pn = 0;
112                 ret = true;
113                 pos[pn++] = sa[b];
114             }
115             b = e = i;
116         }    
117     }
118     if (check(b, e)) {
119         if (!ret)
120             pn = 0;
121         ret = true;
122         pos[pn++] = sa[b];
123     }
124     
125     return ret;
126 }
127 
128 void printSa(int n) {
129     for (int i=1; i<=n; ++i)
130         printf("%d ", sa[i]);
131     putchar(‘\n‘);
132 }
133 
134 void printHeight(int n) {
135     for (int i=1; i<=n; ++i)
136         printf("%d ", height[i]);
137     putchar(‘\n‘);
138 }
139 
140 void solve() {
141     int n = 0, ml = 0;
142     
143     if (ns == 1) {
144         puts(s[0]);
145         return ;
146     }
147     
148     rep(i, 0, ns) {
149         for (int j=0; ; ++j) {
150             if (s[i][j] == ‘\0‘) {
151                 ml = max(ml, j);
152                 break;
153             }
154             id[n] = i;
155             a[n] = s[i][j] - ‘a‘ + 100;
156             ++n;
157         }
158         id[n] = a[n] = i;
159         ++n;
160     }
161     
162     --n;
163     da(a, sa, n+1, 130);
164     calheight(a, sa, n);
165     
166     #ifndef ONLINE_JUDGE
167         // printSa(n);
168         // printHeight(n);
169         // printf("ml = %d\n", ml);
170     #endif
171     
172     int l = 1, r = ml, mid;
173     int ans = 0;
174     ns_ = ns >> 1;
175     
176     while (l <= r) {
177         mid = (l + r) >> 1;
178         if (judge(mid, n)) {
179             ans = mid;
180             l = mid + 1;
181         } else {
182             r = mid - 1;
183         }
184     }
185     
186     if (ans == 0) {
187         puts("?");
188         return ;
189     }
190     
191     char ch;
192     
193     rep(i, 0, pn) {
194         rep(j, 0, ans) {
195             ch = a[pos[i]+j] - 100 + ‘a‘;
196             putchar(ch);
197         }
198         putchar(‘\n‘);
199     }
200 }
201 
202 int main() {
203     ios::sync_with_stdio(false);
204     #ifndef ONLINE_JUDGE
205         freopen("data.in", "r", stdin);
206         freopen("data.out", "w", stdout);
207     #endif
208     
209     int t = 0;
210     
211     while (scanf("%d", &ns)!=EOF && ns) {
212         rep(i, 0, ns)
213             scanf("%s", s[i]);
214         if (t++)
215             putchar(‘\n‘);
216         solve();
217     }
218     
219     #ifndef ONLINE_JUDGE
220         printf("time = %d.\n", (int)clock());
221     #endif
222     
223     return 0;
224 }

数据生成器。

 1 from random import randint, shuffle
 2 import shutil
 3 import string
 4 
 5 
 6 def GenDataIn():
 7     with open("data.in", "w") as fout:
 8         t = 20
 9         bound = 10**3
10         lc = list(string.lowercase)
11         for tt in xrange(t):
12             n = randint(1, 10)
13             fout.write("%d\n" % (n))
14             for i in xrange(n):
15                 length = randint(20, 50)
16                 line = ""
17                 for j in xrange(length):
18                     idx = randint(0, 25)
19                     line += lc[idx]
20                 fout.write("%s\n" % (line))
21         fout.write("0\n")
22         
23                 
24 def MovDataIn():
25     desFileName = "F:\eclipse_prj\workspace\hdoj\data.in"
26     shutil.copyfile("data.in", desFileName)
27 
28     
29 if __name__ == "__main__":
30     GenDataIn()
31     MovDataIn()