[BZOJ1031] [JSOI2007] 字符加密Cipher (后缀数组)

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 char s[200005];
 4 int sa[200005], wv[2][350005], tong[200005];
 5  
 6 bool cmp(int *tmp, int x, int y, int j)
 7 {
 8     return tmp[x] == tmp[y] && tmp[x + j] == tmp[y + j];
 9 }
10  
11 void getsa(int n, int m)
12 {
13     int p = 0, *x = wv[0], *y = wv[1];
14     for(int i = 0; i < n; ++i)
15         ++tong[x[i] = s[i]];
16     for(int i = 1; i < m; ++i)
17         tong[i] += tong[i - 1];
18     for(int i = n - 1; ~i; --i)
19         sa[--tong[x[i]]] = i;
20     for(int j = 1; p != n; j <<= 1, m = p)
21     {
22         p = 0;
23         for(int i = n - j; i < n; ++i)
24             y[p++] = i;
25         for(int i = 0; i < n; ++i)
26             if(sa[i] >= j) y[p++] = sa[i] - j;
27         for(int i = 0; i < m; ++i)
28             tong[i] = 0;
29         for(int i = 0; i < n; ++i)
30             ++tong[x[y[i]]];
31         for(int i = 1; i < m; ++i)
32             tong[i] += tong[i - 1];
33         for(int i = n - 1; ~i; --i)
34             sa[--tong[x[y[i]]]] = y[i];
35         swap(x, y), p = 1, x[sa[0]] = 0;
36         for(int i = 1; i < n; ++i)
37             x[sa[i]] = cmp(y, sa[i - 1], sa[i], j) ? p - 1 : p++;
38     }
39 }
40  
41 int main()
42 {
43     int n;
44     cin >> s;
45     n = strlen(s);
46     for(int i = 0; i < n; ++i)
47         s[i + n] = s[i];
48     getsa(n << 1 | 1, 128);
49     for(int i = 1; i <= n << 1; ++i)
50         if(sa[i] < n) cout << s[sa[i] + n - 1];
51     cout << endl;
52     return 0;
53 }