扩展 KMP(模板) 洛谷P5410

题目：https://www.luogu.org/problemnew/show/P5410

博客

#include<bits/stdc++.h>using namespace std;#define ll long long
#define mem(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3fconst int maxn=1e5+10;int nxt[maxn],extend[maxn];int q;string s,t;void getnxt()
{int l=t.size();nxt[0]=l;int now=0;while(t[now]==t[now+1]&&now+1<l) now++;nxt[1]=now;int p0=1;//可以到达最远位置的ifor(int i=2;i<l;i++){if(i+nxt[i-p0]<nxt[p0]+p0)nxt[i]=nxt[i-p0];else{int now=nxt[p0]+p0-i;now=max(now,0);//这里是为了防止i>p的情况while(t[now]==t[i+now]&&i+now<l)now++;nxt[i]=now;p0=i;}}
}void exkmp()
{getnxt();int now=0;int lim=min(s.size(),t.size());int l=s.size();int l1=t.size();while(s[now]==t[now]&&now<lim)now++;extend[0]=now;int p0=0;for(int i=1;i<l;i++){if(i+nxt[i-p0]<extend[p0]+p0)extend[i]=nxt[i-p0];else{int now=extend[p0]+p0-i;now=max(now,0);while(t[now]==s[i+now]&&now<l1&&now+i<l)now++;extend[i]=now;p0=i;}}
}int main()
{cin>>s>>t;exkmp();int l=t.size(),l1=s.size();for(int i=0;i<l;i++){cout<<nxt[i]<<" ";}cout<<endl;for(int i=0;i<l1;i++){cout<<extend[i]<<" ";}cout<<endl;return 0;
}