字符串处理之后缀数组

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<string.h>
 4 using namespace std;
 5 #define min(x,y) x>y? y:x
 6 #define N 200010
 7 int dp[N][33];
 8 int wa[N], wb[N], wsf[N], wv[N], sa[N];
 9 int ra[N], height[N], s[N];
10 char str[N], str1[N];
11 int cmp(int *r, int a, int b, int k)
12 {
13     return r[a] == r[b] && r[a + k] == r[b + k];
14 }
15 void getsa(int *r, int *sa, int n, int m)
16 {
17     int i, j, p, *x = wa, *y = wb, *t;
18     for (i = 0; i < m; i++)  wsf[i] = 0;
19     for (i = 0; i < n; i++)  wsf[x[i] = r[i]]++;
20     for (i = 1; i < m; i++)  wsf[i] += wsf[i - 1];
21     for (i = n - 1; i >= 0; i--)  sa[--wsf[x[i]]] = i;
22     p = 1;
23     j = 1;
24     for (; p < n; j *= 2, m = p)
25     {
26         for (p = 0, i = n - j; i < n; i++)  y[p++] = i;
27         for (i = 0; i < n; i++)  if (sa[i] >= j)  y[p++] = sa[i] - j;
28         for (i = 0; i < n; i++)  wv[i] = x[y[i]];
29         for (i = 0; i < m; i++)  wsf[i] = 0;
30         for (i = 0; i < n; i++)  wsf[wv[i]]++;
31         for (i = 1; i < m; i++)  wsf[i] += wsf[i - 1];
32         for (i = n - 1; i >= 0; i--)  sa[--wsf[wv[i]]] = y[i];
33         t = x;
34         x = y;
35         y = t;
36         x[sa[0]] = 0;
37         for (p = 1, i = 1; i < n; i++)
38             x[sa[i]] = cmp(y, sa[i - 1], sa[i], j) ? p - 1 : p++;
39     }
40 }
41 void getheight(int *r, int n)
42 {
43     int i, j, k = 0;
44     for (i = 1; i <= n; i++)  ra[sa[i]] = i;
45     for (i = 0; i < n; i++)
46     {
47         if (k)
48             k--;
49         else
50             k = 0;
51         j = sa[ra[i] - 1];
52         while (r[i + k] == r[j + k])
53             k++;
54         height[ra[i]] = k;
55     }
56 }
57 int main()
58 {
59     while (cin >> str)
60     {
61         cin >> str1;
62         int n = 0, len = strlen(str);
63         for (int i = 0; i < len; i++)
64             s[n++] = str[i] - 'a' + 1;
65         s[n++] = 28;
66         len = strlen(str1);
67         for (int i = 0; i < len; i++)
68             s[n++] = str1[i] - 'a' + 1;
69         s[n] = 0;
70         getsa(s, sa, n + 1, 30);
71         getheight(s, n);
72         int max = 0, pos = 0;
73         len = strlen(str);
74         for (int i = 2; i<n; i++)
75         if (height[i]>max)
76         {
77             if (0 <= sa[i - 1] && sa[i - 1] < len&&len < sa[i])
78                 max = height[i];
79             if (0 <= sa[i] && sa[i] < len&&len < sa[i - 1])
80                 max = height[i];
81         }
82         cout << max << endl;
83     }
84     return 0;
85 }