[各种面试题] 最长重复子串-后缀数组

正好练习写一下后缀数组。

#include<iostream>
#include<iterator>
#include<vector>
#include<algorithm>
using namespace std;

struct node
{
	char* s;
	int start;
	node(char* ss,int t):s(ss),start(t){}
	bool operator<(const node& oth)const 
	{
		return strcmp(s,oth.s)<=0;
	}
};

void suffixArray(char* s)
{
	vector<node> sa;
	for(int i=0;s[i]!='\0';i++)
		sa.push_back(node(s+i,i));
	sort(sa.begin(),sa.end());
	vector<int> rank(sa.size());
	for(int i=0;i<sa.size();i++)
		rank[sa[i].start]=i;
	vector<int> height(sa.size());
	int k=0;
	for(int i=0;i<rank.size();i++)
	{
		if(rank[i]==0)
			continue;
		int j=sa[rank[i]-1].start;
		k=max(k-1,0);
		for(;s[i+k]==s[j+k];k++)
			;
		height[rank[i]]=k;
	}
	//最长重复子串
	cout<< "最长重复子串： " <<endl;
	cout << *max_element(height.begin(),height.end()) <<endl;
	cout <<"最长不重叠子串： " <<endl;
	int l =0,r=sa.size()-1;
	int ans=0;
	while(l<=r)
	{
		int mid=(l+r)>>1;
		int wLeft=0,wRight=0;
		int ok=0;
		while(wLeft<sa.size())
		{
			if(wRight>=sa.size()||height[wRight]<mid)
			{
				wLeft=wRight;
				wRight++;
			}
			else
			{
				while(wRight<sa.size()&&height[wRight]>=mid)
					wRight++;
				int minH=sa[wLeft].start;
				int maxH=sa[wLeft].start;
				while(wLeft<wRight)
				{
					minH=min(minH,sa[wLeft].start);
					maxH=max(maxH,sa[wLeft].start);
					wLeft++;
				}
				if(maxH-minH>=mid)
				{
					ok=1;
					break;
				}
			}
		}
		if(ok)
		{
			ans=mid;
			l=mid+1;
		}
		else
		{
			r=mid-1;
		}
	}
	cout<<ans<<endl;
}

char st[100];
int main()
{
	while(scanf("%s",st))
	{
		suffixArray(st);
		cout<<endl;
	}
}