后缀数组

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 #define N 100005
 5 
 6 int m = ‘z‘ + 1;
 7 int len, buc[N], x[N], y[N], sa[N], rank[N], h[N];
 8 char s[N]; 
 9 
10 inline void build_sa()
11 {
12     scanf("%s", s); len = strlen(s);
13     int i, k, p;
14     for(i = 0; i < m; i++) buc[i] = 0;
15     for(i = 0; i < len; i++) buc[x[i] = s[i]]++;
16     for(i = 1; i < m; i++) buc[i] += buc[i - 1];
17     for(i = len - 1; i >= 0; i--) sa[--buc[x[i]]] = i;
18     for(k = 1; k <= len; k <<= 1)
19     {
20         p = 0;
21         for(i = len - 1; i >= len - k; i--) y[p++] = i;
22         for(i = 0; i < len; i++) if(sa[i] >= k) y[p++] = sa[i] - k;
23         for(i = 0; i < m; i++) buc[i] = 0;
24         for(i = 0; i < len; i++) buc[x[y[i]]]++;
25         for(i = 1; i < m; i++) buc[i] += buc[i - 1];
26         for(i = len - 1; i >= 0; i--) sa[--buc[x[y[i]]]] = y[i];
27         std::swap(x, y);
28         p = 1, x[sa[0]] = 0;
29         for(i = 1; i < len; i++)
30             x[sa[i]] = y[sa[i - 1]] == y[sa[i]] && y[sa[i - 1] + k] == y[sa[i] + k] ? p - 1 : p++;
31         if(p >= len) break;
32         m = p;
33     }
34 }
35 
36 int main()
37 {
38     int i, j, k = 0;
39     build_sa();
40     for(i = 0; i < len; i++) printf("%d ", sa[i] + 1);
41     puts("");
42     for(i = 0; i < len; i++) rank[sa[i]] = i;
43     for(i = 0; i < len; i++)
44     {
45         if(rank[i] == 0)
46         {
47             h[0] = 0;
48             continue;
49         }
50         if(k) k--;
51         j = sa[rank[i] - 1];
52         while(s[i + k] == s[j + k] && i + k < len && j + k < len) k++;
53         h[rank[i]] = k;
54     }
55     for(i = 1; i < len; i++) printf("%d ", h[i]);
56     puts("");
57     return 0;
58 }