后缀数组个人理解

#include<bits/stdc++.h>
#define MAXN 1000005
using namespace std;

int tong[MAXN],sa[MAXN],tp[MAXN],rank[MAXN],n,m;
char a[MAXN];

int get(char c) {
	if(c >= '0' && c <= '9') return c - '0' + 1;
	if(c >= 'A' && c <= 'Z') return c - 'A' + 11;
	return c - 'a' + 37;
}

void Debug(){
	cout<<"下标   :";for(int i = 1 ; i <= n ; i++)cout<<i<<" ";
	cout<<endl;
	cout<<"sa   :";for(int i = 1 ; i <= n ; i++)cout<<sa[i]<<" ";
	cout<<endl;
	cout<<"rank   :";for(int i = 1 ; i <= n ; i++)cout<<rank[i]<<" ";
	cout<<endl;
	cout<<"tp   :";for(int i = 1 ; i <= n ; i++)cout<<tp[i]<<" ";
	cout<<endl;
	cout<<endl<<endl;
}

void rsort(){
	for(int i = 0 ; i <= m ; i++)tong[i] = 0;
	for(int i = 1 ; i <= n ; i++)tong[rank[i]]++;
	for(int i = 1 ; i <= m ; i++)tong[i] += tong[i - 1];
	for(int i = n ; i >= 1 ; i--){
			sa[tong[rank[tp[i]]]--] = tp[i];
	}
}

void init(){
	scanf("%s" , a + 1);n = strlen(a + 1);m = 62;
	for(int i = 1 ; i <= n ; i++)rank[i] = get(a[i]) , tp[i] = i;
	rsort();
}

void solve(){
	for(int w = 1 , p = 0 ; w <= n ; w = (w + w) , m = p , p = 0){
		for(int i = n - w + 1 ; i <= n ; i++)tp[++p] = i;
		for(int i = 1 ; i <= n ; i++)if(sa[i] > w)tp[++p] = sa[i] - w;
		rsort();
		swap(rank , tp);
		rank[sa[1]] = p = 1;
		for(int i = 2 ; i <= n ; i++)
		rank[sa[i]] = (tp[sa[i]] == tp[sa[i - 1]] && tp[sa[i] + w] == tp[sa[i - 1] + w]) ? p : ++p;		
		if(p == n)break;
	}
	for(int i = 1 ; i <= n ; i++)cout<<sa[i]<<" ";
}

int main(){
	init();
	solve();
}