제출 #418982

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
418982		Dymo	회문 (APIO14_palindrome)	C++14	73 / 100	1089 ms	54256 KiB

palindrome

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

#define ll   long long
#define ull  long long
#define ull  long long
#define pll pair<ll,ll>
#define ff first
#define ss second
#define pb push_back
//#define endl "\n"
const ll maxn =1e6+5;
const ll mod=988642507;
const ll mod1=999242501;
const ll base=317;
const ll base1=293;
ull f[maxn];
ull f1[maxn];
ull fv[maxn];
ull fv1[maxn];

ull mu[maxn];
ull mu1[maxn];

ll n;
ll cntnw=0;
map<pair<ull,ull>,ll> mp;
ll cnt[maxn];
ll len[maxn];
ll nxt[maxn];
ll in[maxn];
bool add(pair<ull,ull> val,ll len1)
{
    if (!mp.count(val))
    {
        cntnw++;
        len[cntnw]=len1;
        mp[val]=cntnw;
        return true;
    }
    return false;

}
pair<ull,ull> get(ll l,ll r)
{
    return make_pair((((f[r]-f[l-1]*mu[r-l+1])%mod+mod)%mod),(((f1[r]-f1[l-1]*mu1[r-l+1])%mod1+mod1)%mod1));
}
pair<ull,ull> getv(ll l,ll r)
{
    swap(l,r);
    l=n-l+1;
    r=n-r+1;
    return make_pair((((fv[r]-fv[l-1]*mu[r-l+1])%mod+mod)%mod),(((fv1[r]-fv1[l-1]*mu1[r-l+1])%mod1+mod1)%mod1));
}
bool chk(ll l,ll r)
{
    ll len=(r-l+1)/2;
    if(get(r-len+1,r)==getv(l,l+len-1)) return true;
    return false;
}
ll val[maxn];
ll val1[maxn];

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    if (fopen("test.inp","r"))
    {
        freopen("test.inp","r",stdin);
        freopen("test.out","w",stdout);
    }
    mt19937_64 rd(time(NULL));
    mu[0]=1;
    mu1[0]=1;
    for (int i=1; i<maxn; i++)
        mu[i]=(mu[i-1]*base)%mod, mu1[i]=(mu1[i-1]*base1)%mod1;
         for (int i=1; i<=26; i++)
    {
        val[i]=abs((ll)rd())%mod;
        val1[i]=abs((ll)rd())%mod1;
    }
    string s;
    cin>> s;
    string t=s;
    n=s.length();
    s=" "+ s;
    for (int i=1; i<=n; i++)
    {
        f[i]=(f[i-1]*base+val[s[i]-'a'+1])%mod;
        f1[i]=(f1[i-1]*base1+val1[s[i]-'a'+1])%mod1;
    }
    reverse(t.begin(),t.end());
    t=" "+t;
    for (int i=1; i<=n; i++)
    {
        fv[i]=(fv[i-1]*base+val[t[i]-'a'+1])%mod;
        fv1[i]=(fv1[i-1]*base1+val1[t[i]-'a'+1])%mod1;
    }

    ll ans=0;
    for (ll i=1; i<=n; i++)
    {
        ll lenmx=min(i,n-i+1);
        ll l=1,h=lenmx;
        while (l<=h)
        {
            ll mid=(l+h)/2;
            if (get(i,i+mid-1)==getv(i-mid+1,i)) l=mid+1;
            else h=mid-1;
        }

      //  if (i==2)cout <<get(2,3)<<" "<<getv(1,2)<<" "<<h<<endl;
     // cout <<i<<" "<<h<<endl;
        ll pre=-1;
        for (int j=h;j>=1;j--)
        {
         //   cout <<j<<endl;
            auto p=add(get(i,i+j-1),j*2-1);
            if (j==h) cnt[mp[get(i,i+j-1)]]++;
            if (pre!=-1) nxt[pre]=mp[get(i,i+j-1)];
            ll t=pre;
            pre=mp[get(i,i+j-1)];
           if (t!=-1) in[pre]++;
            //cout <<mp[get(i,i+j-1)]<<" "<<i<<" "<<i+j-1<<endl;
            if (!p) break;
        }
    }
    queue<ll> q;
   for (int i=1;i<=cntnw;i++)
   {
        if (!in[i]) q.push(i);
   }
 //  cout <<q.size()<<"db"<<endl;
   while (!q.empty())
   {
       auto p=q.front();
       q.pop();
       if (nxt[p]!=0)
       {
           cnt[nxt[p]]+=cnt[p];
           in[nxt[p]]--;
           if (!in[nxt[p]]) q.push(nxt[p]);
       }
       ans=max(ans,cnt[p]*len[p]);
   }
   for (int i=1;i<=cntnw;i++) in[i]=0, len[i]=0, nxt[i]=0, cnt[i]=0;
   cntnw=0;
   mp.clear();
   for (ll i=2; i<=n; i++)
    {
        ll lenmx=min(i-1,n-i+1);
        ll l=1,h=lenmx;
        while (l<=h)
        {
            ll mid=(l+h)/2;
            if (get(i,i+mid-1)==getv(i-mid,i-1)) l=mid+1;
            else h=mid-1;
        }
        ll pre=-1;
        for (int j=h;j>=1;j--)
        {
            auto p=add(get(i,i+j-1),j*2);
            if (j==h) cnt[mp[get(i,i+j-1)]]++;
            if (pre!=-1) nxt[pre]=mp[get(i,i+j-1)];
            ll t=pre;
            pre=mp[get(i,i+j-1)];
            if (t!=-1) in[pre]++;
            if (!p) break;
        }
    }
   for (int i=1;i<=cntnw;i++)
   {
        if (!in[i]) q.push(i);
   }
   while (!q.empty())
   {
       auto p=q.front();
       q.pop();
       if (nxt[p]!=0)
       {
           cnt[nxt[p]]+=cnt[p];
           in[nxt[p]]--;
           if (!in[nxt[p]]) q.push(nxt[p]);
       }
       ans=max(ans,cnt[p]*len[p]);
   }
   cout <<ans;


}

컴파일 시 표준 에러 (stderr) 메시지

palindrome.cpp: In function 'int main()':
palindrome.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen("test.inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen("test.out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 0 / 27