BZOJ1031: [JSOI2007]字符加密Cipher - 后缀数组 -

  1 #include<map>
  2 #include<set>
  3 #include<cmath>
  4 #include<ctime>
  5 #include<deque>
  6 #include<queue>
  7 #include<stack>
  8 #include<cstdio>
  9 #include<vector>
 10 #include<climits>
 11 #include<cstring>
 12 #include<cstdlib>
 13 #include<iostream>
 14 #include<algorithm>
 15 using namespace std;
 16 typedef long long LL;
 17 const int Maxn=1000000+1;
 18 struct Suffix_Array
 19 {
 20     int c[Maxn];
 21     int sa[Maxn];
 22     void Sort(int *x,int *y,int n,int m)
 23     {
 24         for(int i=0;i<=m;i++)c[i]=0;
 25         for(int i=1;i<=n;i++)c[x[y[i]]]++;
 26         for(int i=1;i<=m;i++)c[i]+=c[i-1];
 27         for(int i=n;i>=1;i--)sa[c[x[y[i]]]--]=y[i];
 28     }
 29     bool Same(int *s,int x,int y,int l)
 30     {
 31         return s[x]==s[y]&&s[x+l]==s[y+l];
 32     }
 33     int t1[Maxn];
 34     int t2[Maxn];
 35     int rank[Maxn];
 36     int height[Maxn];
 37     void Init(int n)
 38     {
 39         for(int i=1;i<=n;i++)sa[i]=0;
 40     }
 41     void Build(int *s,int n,int m)
 42     {
 43         Init(n);
 44         int *x=t1;
 45         int *y=t2;
 46         for(int i=1;i<=n;i++)x[i]=i;
 47         Sort(s,x,n,m);
 48         for(int i=1;i<=n;i++)x[i]=s[i];
 49         for(int j=1;j<=n;j<<=1)
 50         {
 51             int p=0;
 52             for(int i=n-j+1;i<=n;i++)y[++p]=i;
 53             for(int i=1;i<=n;i++)
 54                 if(j<sa[i])y[++p]=sa[i]-j;
 55             Sort(x,y,n,m);
 56             swap(x,y);
 57             int k=0;
 58             x[sa[1]]=++k;
 59             for(int i=2;i<=n;i++)
 60             {
 61                 if(!Same(y,sa[i-1],sa[i],j))k++;
 62                 x[sa[i]]=k;
 63             }
 64             m=k;
 65         }
 66         for(int i=1;i<=n;i++)rank[sa[i]]=i;
 67         int h=0;
 68         height[1]=0;
 69         for(int i=1;i<=n;i++)
 70         {
 71             if(h!=0)h--;
 72             if(rank[i]==1)continue;
 73             int j=sa[rank[i]-1];
 74             while(s[i+h]==s[j+h])h++;
 75             height[rank[i]]=h;
 76         }
 77     }
 78 }suf;
 79 int a[Maxn];
 80 char str[Maxn];
 81 int main()
 82 {
 83     // freopen("a.in","r",stdin);
 84     // freopen("a.out","w",stdout);
 85     gets(str+1);
 86     int len=strlen(str+1);
 87     int n=len*2;
 88     for(int i=1;i<=len;i++)a[i]=str[i];
 89     for(int i=len+1;i<=n;i++)a[i]=str[i-len];
 90     suf.Build(a,n,130);
 91     int p=1;
 92     for(int i=1;i<=len;i++)
 93     {
 94         while(len<suf.sa[p])p++;
 95         printf("%c",a[suf.sa[p]+len-1]);
 96         p++;
 97     }
 98     printf("\n");
 99     return 0;
100 }