poj2217 Secretary 后缀数组

#include <iostream>
#include <cstring>
#include <string>
#include <cstdio>
using namespace std;
int T, n, m, p, len, r[20005], c[20005], x[20005], y[20005], sa[20005];
int rank[20005], ans, hei[20005];
string s, t;
void getSa(){
	r[n++] = 0;
	for(int i=0; i<m; i++)	c[i] = 0;
	for(int i=0; i<n; i++)	c[x[i]=r[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 j=1; p<n; j*=2, m=p){
		p = 0;
		for(int i=n-j; i<n; i++)	y[p++] = i;
		for(int i=0; i<n; i++)	if(sa[i]>=j)	y[p++] = sa[i] - j;
		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++)
			if(y[sa[i-1]]==y[sa[i]] && y[sa[i-1]+j]==y[sa[i]+j])
				x[sa[i]] =  p - 1;
			else
				x[sa[i]] = p++;
	}
	n--;
}
void getLcp(){
	int h=0;
	for(int i=1; i<=n; i++)	rank[sa[i]] = i;
	for(int i=0; i<n; i++){
		if(h)	h--;
		int j=sa[rank[i]-1];
		while(r[i+h]==r[j+h])	h++;
		hei[rank[i]] = h;
	}
}//构建height数组
int main(){
	cin>>T;
	getline(cin, s);
	while(T--){
		getline(cin, s);
		getline(cin, t);
		len = s.size();
		s = s + "$" + t;
		n = s.size();
		m = 128;
		ans = p = 0;
		for(int i=0; i<n; i++)	r[i] = (int)s[i];
		getSa();
		getLcp();
		for(int i=2; i<=n; i++)
			if((sa[i-1]<len)^(sa[i]<len))
				ans = max(ans, hei[i]);
		printf("Nejdelsi spolecny retezec ma delku %d.\n", ans);
	}
	return 0;
}