HYSBZ - 1031 字符加密Cipher

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1050010;
#define F(x) ((x)/3+((x)%3==1?0:tb))
#define G(x) ((x)<tb?(x)*3+1:((x)-tb)*3+2)
int wa[MAXN*3],wb[MAXN*3],wv[MAXN*3],wss[MAXN*3];
int c0(int *r,int a,int b)
{
return r[a] == r[b] && r[a+1] == r[b+1] && r[a+2] == r[b+2];
} 
int c12(int k,int *r,int a,int b)
{
if(k == 2)
return r[a] < r[b] || ( r[a] == r[b] && c12(1,r,a+1,b+1) );
else return r[a] < r[b] || ( r[a] == r[b] && wv[a+1] < wv[b+1] );
}
void sort(int *r,int *a,int *b,int n,int m)
{
int i;
for(i = 0;i < n;i++)wv[i] = r[a[i]]; for(i = 0;i < m;i++)wss[i] = 0; for(i = 0;i < n;i++)wss[wv[i]]++;
for(i = 1;i < m;i++)wss[i] += wss[i-1];
for(i = n-1;i >= 0;i--)
b[--wss[wv[i]]] = a[i];
}
void dc3(int *r,int *sa,int n,int m)
{
int i, j, *rn = r + n;
int *san = sa + n, ta = 0, tb = (n+1)/3, tbc = 0, p; r[n] = r[n+1] = 0;
for(i = 0;i < n;i++)if(i %3 != 0)wa[tbc++] = i; sort(r + 2, wa, wb, tbc, m);
sort(r + 1, wb, wa, tbc, m);
sort(r, wa, wb, tbc, m);
for(p = 1, rn[F(wb[0])] = 0, i = 1;i < tbc;i++) rn[F(wb[i])] = c0(r, wb[i-1], wb[i]) ? p - 1 : p++;
if(p < tbc)dc3(rn,san,tbc,p);
else for(i = 0;i < tbc;i++)san[rn[i]] = i;
for(i = 0;i < tbc;i++) if(san[i] < tb)wb[ta++] = san[i] * 3;
if(n % 3 == 1)wb[ta++] = n - 1; sort(r, wb, wa, ta, m);
for(i = 0;i < tbc;i++)wv[wb[i] = G(san[i])] = i;
for(i = 0, j = 0, p = 0;i < ta && j < tbc;p++)
sa[p] = c12(wb[j] % 3, r, wa[i], wb[j]) ? wa[i++] : wb[j++];
for(;i < ta;p++)sa[p] = wa[i++];
for(;j < tbc;p++)sa[p] = wb[j++];
} 
char s[MAXN]; 
int a[MAXN];
int sa[MAXN];
int main()
{
	while(gets(s)!=NULL)
	{
	int n=strlen(s);
	for (int i=n;i<2*n;i++) s[i]=s[i-n];
	for (int i=0;i<2*n;i++) a[i]=s[i];
	a[2*n]=0;
	dc3(a,sa,2*n+1,300);
	int num=0;
	for (int i=1;i<=2*n;i++){
		int p; 
	//	cout<<s+sa[i]<<endl;continue;
		if (2*n-sa[i]<n||sa[i]>=n) continue;
		num++;
		p=sa[i]+n-1;
		putchar(s[p]);
		if(num>=n) break;
		}
	}
    return 0;
}