Submission #39936

#	Time	Username	Problem	Language	Result	Execution time	Memory
39936		imaxblue	Palindromes (APIO14_palindrome)	C++14	73 / 100	44 ms	131072 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pb push_back
#define x first
#define y second
#define pii pair<int, int>
#define p3i pair<pii, int>
#define pll pair<ll, ll>
#define p3l pair<pll, ll>
#define lseg L, (L+R)/2, N*2+1
#define rseg (L+R)/2+1, R, N*2+2
#define ub upper_bound
#define lb lower_bound
#define pq priority_queue
#define MN 1000000007
#define fox(k, x) for (int k=0; k<x; ++k)
#define fox1(k, x) for (int k=1; k<=x; ++k)
#define foxr(k, x) for (int k=x-1; k>=0; --k)
#define fox1r(k, x) for (int k=x; k>0; --k)
#define ms multiset
#define flood(x) memset(x, 0x3f3f3f3f, sizeof x)
#define drain(x) memset(x, 0, sizeof x)
#define rng() (rand() >> 3)*rand()
#define scan(X) do{while((X=getchar())<'0'); for(X-='0'; '0'<=(_=getchar()); X=(X<<3)+(X<<1)+_-'0');}while(0)
char _;
#define pi 3.14159265358979323846

int p=-1, ch;
string s;
struct node{
    node* c[27];
    node* fail[27];
    vector<node*> nxt;
    int cnt, len;
    node(){
        cnt=0; len=-1;
        fox(l, 26){c[l]=fail[l]=0;}
        nxt=vector<node*>();
    }
    node(node*P){
        //cout << "^" << P->len << endl;
        len=0; cnt=0;
        fox(l, 26) c[l]=0;
        P->nxt.pb(this);
        fox(l, 26){
            fail[l]=P;
        }
    }
    node(node*P, int L){
        //cout << "&";
        len=L; cnt=0;
        fox(l, 26) c[l]=0;
        if (L>1){
            P=P->fail[ch];
            while(p-1-P->len<0 || s[p-1-P->len]!=s[p]) P=P->fail[ch];
            P=P->c[ch];
        }
        P->nxt.pb(this);
        fox(l, 26){
            if (s[p-P->len]-'a'==l) fail[l]=P;
            else fail[l]=P->fail[l];
        }
    }
}*root, *r2, *last;
void add(node*N){
    while(p-1-N->len<0 || s[p-1-N->len]!=s[p]){
        N=N->fail[ch];
    }
    //cout << "*" << N->len << endl;
    if (N->c[ch]==0){
        if (N->len==-1) N->c[ch]=new node(r2, 1);
        else N->c[ch]=new node(N, N->len+2);
    }
    last=N->c[ch];
    N->c[ch]->cnt++;
}
ll ans;
void dfs(node*N){
    fox(l, N->nxt.size()){
        dfs(N->nxt[l]);
        N->cnt+=N->nxt[l]->cnt;
    }
    ans=max(ans, 1LL*N->cnt*N->len);
}
int main(){
    root=new node();
    last=r2=new node(root);
    cin >> s;
    for(p=0; p<s.size(); ++p){
        ch=s[p]-'a';
        add(last);
        //cout << p << endl;
    }
    dfs(root);
    cout << ans;
    return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'void dfs(node*)':
palindrome.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(k, x) for (int k=0; k<x; ++k)
                                  ^
palindrome.cpp:81:5: note: in expansion of macro 'fox'
     fox(l, N->nxt.size()){
     ^
palindrome.cpp: In function 'int main()':
palindrome.cpp:91:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(p=0; p<s.size(); ++p){
               ^

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