Long Long Message POJ - 2774

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 using namespace std;
 6 const int maxn = 200010;
 7 char s[maxn];
 8 int sa[maxn],t1[maxn],t2[maxn],c[maxn];
 9 int rank[maxn],height[maxn];
10 
11 
12 void build_sa(int n, int m){
13     int i, *x = t1, *y = t2;
14     for(i = 0; i < m; i++) c[i] = 0;
15     for(i = 0; i < n; i++) c[x[i] = s[i]]++;
16     for(i = 1; i < m; i++) c[i] += c[i-1];
17     for(i = n-1; i >= 0; i--) sa[--c[x[i]]] = i;
18     for(int k = 1; k <= n; k <<= 1){
19         int p = 0;
20         for(i = n-k; i < n; i++) y[p++] = i;
21         for(i = 0; i < n; i++) if(sa[i] >= k) y[p++] = sa[i] - k;
22         for(i = 0; i < m; i++) c[i] = 0;
23         for(i = 0; i < n; i++) c[x[y[i]]]++;
24         for(i = 1; i < m; i++) c[i] += c[i-1];
25         for(i = n-1; i >= 0; i--) sa[--c[x[y[i]]]] = y[i];
26         swap(x,y);
27         p=1;
28         x[sa[0]]=0;
29         for(i = 1; i < n; i++) 
30           x[sa[i]]= y[sa[i]]==y[sa[i-1]] && y[sa[i]+k]==y[sa[i-1]+k] ? p-1 : p++;
31         if(p >= n) break;
32         m=p;
33     }
34 }
35 void getHeight(int n){
36     int i, j, k=0;
37     for(i = 0; i <= n; i++) rank[sa[i]] = i;
38     for(i = 0; i < n; i++) {
39         if(k) k--;
40         j = sa[rank[i]-1];
41         while(s[i+k]==s[j+k]) k++;
42         height[rank[i]] = k;
43     }
44 }
45 
46 int main(){
47     while(scanf("%s",s)!=EOF){
48         int n=strlen(s);
49         int l1=n;
50         s[n]=‘#‘;
51         scanf("%s",s+n+1);
52         n=strlen(s);
53     //    cout<<s<<endl;
54         build_sa(n+1,256);
55         getHeight(n);
56         int ans=0;
57         for(int i = 1; i < n; i++){
58             if(sa[i]<l1&&sa[i-1]>l1 || sa[i]>l1&&sa[i-1]<l1){
59                 ans=max(ans,height[i]);
60             }
61         }
62         printf("%d\n",ans);
63     }
64     return 0;
65 }