Codeforces Round #516 (Div. 1, by Moscow Team Olympiad) F

题链

Description

  字符串拆分

Code

#include<bits/stdc++.h>
#define ULL unsigned long long
#define N 500007
#define Ha 100000007
using namespace std;
unordered_map<ULL,int> mp;
ULL pre[N],Bas[N];
ULL pos(int st,int len){
    return pre[st+len-1]-pre[st-1]*Bas[len];
}
bool pan(int st,int len,int edg){
    static ULL has; 
    return has=pos(st,len),mp.count(has)&&mp[has]>=edg;
}
bool gao(int st,int len) {
    static ULL has; static bool oo;
    has=pos(st,len);
//    cout<<has<<endl;
    if (mp.count(has)) return 1;
    mp[has]=st; return 0;
//    return has=pos(st,len),cout<<has<<endl,oo=mp.count(has),mp[has]=max(st,mp,oo;
}
int n,dp[N],opk,ans;char p[N];
signed main() {
//    freopen("6.txt","r",stdin);
    scanf("%d",&n);
    scanf("%s",p+1);
    mp[0]=n+1; Bas[0]=1;
    for (int i=1;i<=n;i++) {
        pre[i]=pre[i-1]*Ha+p[i]-'a'+1;
        Bas[i]=Bas[i-1]*Ha;
    }
    dp[n+1]=0;
    for (int i=n;i;i--) {
        opk=dp[i+1]+2;
        do {opk--;} 
         while (!pan(i,opk-1,i+opk)&&!pan(i+1,opk-1,i+opk));
        dp[i]=opk; ans=max(ans,opk);
        for (int j=opk;j;j--) if (gao(i,j)) break;
    }
    return printf("%d
",ans),0; 
}