Submission #1196965

#	Time	Username	Problem	Language	Result	Execution time	Memory
1196965		Malix	Palindromes (APIO14_palindrome)	C++20	0 / 100	78 ms	196608 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<ll,ll,ll> ti;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))

ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;

struct node{
    int sz;
    int next[26];
    int suf;
};

int n,pos=2,cnt[200002];
string s;
vector<node> a(2000002);
int suff=0;

void letter(int x){
    int c=s[x]-'a';
    if(a[suff].sz==x)suff=a[suff].suf;
    while(suff>0&&s[x-1-a[suff].sz]!=s[x])suff=a[suff].suf;
    if(a[suff].next[c]==-1){
        a[suff].next[c]=pos;
        a[pos].sz=a[suff].sz+2;
        suff=a[suff].suf;
        while(suff>0&&s[x-1-a[suff].sz]!=s[x])suff=a[suff].suf;
        a[pos].suf=a[suff].next[c];
        if(a[pos].sz==1)a[pos].suf=1;
        cnt[pos]++;
        suff=pos;
        pos++;
    }
    else{
        cnt[a[suff].next[c]]++;
        suff=a[suff].next[c];
    }
    
}

int main() {   
// ios::sync_with_stdio(0);
// cin.tie(0);
freopen("test_input.txt", "r", stdin);
freopen("test_output.txt", "w", stdout);
    cin>>s;
    n=s.size();
    memset(cnt,0,sizeof(cnt));
    REP(i,0,n+2)REP(j,0,26)a[i].next[j]=-1;
    a[0].sz=-1;a[0].suf=0;
    a[1].sz=0;a[1].suf=0;
    REP(i,0,n)letter(i);
    priority_queue<pi> pq;
    REP(i,2,n+2)pq.push({a[i].sz,i});
    ll ans=0;
    REP(i,0,n){
        int x=pq.top().S;
        ans=max(ans,(ll)a[x].sz*(ll)cnt[x]);
        cnt[a[x].suf]+=cnt[x];
        pq.pop();
    }
    cout<<ans;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:59:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 | freopen("test_input.txt", "r", stdin);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:60:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 | freopen("test_output.txt", "w", stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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