洛谷 P3809 【模板】后缀排序（后缀数组）

http://www.cnblogs.com/jinkun113/p/4743694.html
https://www.luogu.org/blog/black-jokers/solution1-p3809
https://xminh.github.io/2018/02/27/%E5%90%8E%E7%BC%80%E6%95%B0%E7%BB%84-%E6%9C%80%E8%AF%A6%E7%BB%86(maybe)%E8%AE%B2%E8%A7%A3.html

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn=2e6+10;
int n,m,a[maxn],buc[maxn],x[maxn],y[maxn],sa[maxn];
char s[maxn];

void radix(){
    memset(buc,0,sizeof(buc));
    for(int i=1;i<=n;i++) buc[x[y[i]]]++;
    for(int i=2;i<=m;i++) buc[i]+=buc[i-1];
    for(int i=n;i>=1;i--) sa[buc[x[y[i]]]--]=y[i];
}

void getsa(){
    m=62;
    for(int i=1;i<=n;i++) x[i]=a[i],y[i]=i;
    radix();
    for(int k=1;k<=n;k<<=1){
        int p=0;
        for(int i=n-k+1;i<=n;i++) y[++p]=i;
        for(int i=1;i<=n;i++) if(sa[i]>k) y[++p]=sa[i]-k;
        radix();
        swap(x,y);
        x[sa[1]]=1,p=1;
        for(int i=2;i<=n;i++)
            x[sa[i]]=y[sa[i]]==y[sa[i-1]]&&y[sa[i]+k]==y[sa[i-1]+k]?p:++p;
        if(p==n) break;
        m=p;
    }
}

int main(){
    scanf("%s",s);
    int len=strlen(s);
    for(int i=0;i<len;i++){
        if(s[i]>='0'&&s[i]<='9') a[++n]=s[i]-'0'+1;
        else if(s[i]>='A'&&s[i]<='Z') a[++n]=s[i]-'A'+11;
        else a[++n]=s[i]-'a'+37;
    }
    getsa();
    for(int i=1;i<=n;i++){
        if(i!=1) putchar(' ');
        printf("%d",sa[i]);
    }
    putchar('\n');
    return 0;
}