B-Suffix Array

#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <map>
#include <stack>
#include <set>
#include <queue>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <ctime>
#include <bitset>
#include <cmath>
#include <sstream>
#include <iostream>
#include <unordered_map>
 
#define ll long long
#define ull unsigned long long
#define ls nod<<1
#define rs (nod<<1)+1
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define INF 0x3f3f3f3f
#define max(a, b) (a>b?a:b)
#define min(a, b) (a<b?a:b)
 
 
const double eps = 1e-2;
const int maxn = 2e5 + 10;
const ll MOD = 99999999999999;
const int mlog=20;
 
int sgn(double a) { return a < -eps ? -1 : a < eps ? 0 : 1; }
 
using namespace std;
 
struct Suffix_Array
{
    int s[maxn],sa[maxn],rk[maxn],height[maxn];
    int t[maxn],t2[maxn],c[maxn],n;
    void init()
    {
        memset(t, 0, sizeof(int) * (2 * n + 10));
        memset(t2, 0, sizeof(int) * (2 * n + 10));
    }
    void build_sa(int m=256)
    {
        int *x = t, *y = t2;
        for(int i=0;i<m;++i) c[i]=0;
        for(int i=0;i<n;++i) c[x[i]=s[i]]++;
        for(int i=1;i<m;++i) c[i]+=c[i-1];
        for(int i=n-1;i>=0;--i) sa[--c[x[i]]]=i;
        for(int k=1;k<=n;k<<=1){
            int p=0;
            for(int i=n-1;i>=n-k;--i) y[p++]=i;
            for(int i=0;i<n;++i) if(sa[i]>=k) y[p++]=sa[i]-k;
            for(int i=0;i<m;++i) c[i]=0;
            for(int i=0;i<n;++i) c[x[y[i]]]++;
            for(int i=1;i<m;++i) c[i] += c[i - 1];
            for(int i=n-1;i>=0;--i) sa[--c[x[y[i]]]]=y[i];
            swap(x,y);
            p=1;
            x[sa[0]]=0;
            for(int i=1;i<n;++i)
                x[sa[i]]=y[sa[i-1]]==y[sa[i]]&&y[sa[i-1]+k]==y[sa[i]+k]?p-1:p++;
            if(p>=n) break;
            m=p;
        }
    }
    void get_height()
    {
        int k=0;
        for(int i=0;i<n;++i) rk[sa[i]]=i;
        for(int i=0;i<n;++i){
            if(rk[i]>0){
                if(k) --k;
                int j=sa[rk[i]-1];
                while(i+k<n&&j+k<n&&s[i+k]==s[j+k]) ++k;
                height[rk[i]]=k;
            }
        }
    }
    int d[maxn][mlog],Log[maxn];
    void RMQ_init()
    {
        Log[0]=-1;
        for(int i=1;i<=n;++i) Log[i]=Log[i/2]+1;
        for(int i=0;i<n;++i) d[i][0]=height[i];
        for(int j=1;j<=Log[n];++j){
            for(int i=0;i+(1<<j)-1<n;++i){
                d[i][j]=min(d[i][j-1],d[i+(1<<(j-1))][j-1]);
            }
        }
    }
    int lcp(int i,int j)//返回下标i开始的后缀与下标j开始的后缀的最长公共前缀。
    {
        if(i==j) return n-i;
        if(rk[i]>rk[j]) swap(i,j);
        int x=rk[i]+1,y=rk[j];
        int k=Log[y-x+1];
        return min(d[x][k],d[y-(1<<k)+1][k]);
    }
    pair <int, int> Locate(int l, int r)//返回一个最长的区间[L, R]使得sa中下标从L到R的所有后缀都以s[l, r]为前缀。
    {
        int pos=rk[l],length=r-l+1;
        int L=0,R=pos,M;
        while(L<R){
            M=(L+R)>>1;
            if(lcp(l,sa[M])>=length) R=M;
            else L=M+1;
        }
        int tmp=L;
        L=pos,R=n-1;
        while(L<R){
            M=(L+R+1)>>1;
            if(lcp(l,sa[M])>=length) L=M;
            else  R=M-1;
        }
        return make_pair(tmp,L);
    }
}SA;
 
int n;
int b[maxn],dis[maxn],ans[maxn];
char s[maxn];
 
bool cmp(int i,int j) {
    if (dis[i] != dis[j])
        return dis[i] < dis[j];
    if (i + dis[i] >= n && j + dis[j] >= n)
        return i > j;
    if (i + dis[i] >= n)
        return 1;
    if (j + dis[j] >= n)
        return 0;
    int lcp = SA.lcp(i+dis[i],j+dis[j]);
    return b[i + dis[i] + lcp] < b[j + dis[j] + lcp];
}
 
int main() {
    while (~scanf("%d",&n)) {
        b[n] = 0;    // 这里需要特别注意 （后缀数组最后一个都需要特殊处理）
        scanf("%s",s);
        int fla = -1,flb = -1;
        for (int i = 0;i < n;i++) {
            if (s[i] == ‘a‘) {
                if (fla != -1)
                    b[i] = i - fla;
                else
                    b[i] = 0;
                fla = i;
            }
            else {
                if (flb != -1)
                    b[i] = i - flb;
                else
                    b[i] = 0;
                flb = i;
            }
        }
        SA.n = n;
        for (int i = 0;i < n;i++)
            SA.s[i] = b[i];
        SA.init();
        SA.build_sa();
        SA.get_height();
        SA.RMQ_init();
        dis[n - 1] = 2;
        for (int i = n - 2;i >= 0;i--) {
            if (s[i] == s[i+1])
                dis[i] = dis[i+1] + 1;
            else
                dis[i] = 2;
        }
        for (int i = 0;i < n;i++)
            ans[i] = i;
        sort(ans,ans+n,cmp);
        for (int i = 0;i < n;i++)
            printf("%d ",ans[i]+1);
        printf("\n");
    }
    return 0;
}