Submission #798220

#	Time	Username	Problem	Language	Result	Execution time	Memory
798220		alittlemiddle	Palindromes (APIO14_palindrome)	C++14	0 / 100	10 ms	6624 KiB

palindrome

#include <bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
//#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=2e6+11;
int d1[N], d2[N], tmp[N];
string s;
void manacher1(string s, int* p)
{
    int n=s.length();
    s = "<"+s+">";
    int l=0, r=1;
    for(int i=1; i<=n; i++)
    {
        if(i>r) p[i]=0;
        else p[i]=min(r-i, p[l+r-i]);
        while(1<=i-p[i] && i+p[i]<=n && s[i-p[i]]==s[i+p[i]]) p[i]++; // mo rong p[i]
        p[i]--; // bo tam
        if(i+p[i]>r)
        {
            l=i-p[i];
            r=i+p[i];
        }
    }
}
void manacher2(string s, int* p)
{
    int n = s.length();
    string s1 = "";
    for(char v: s) s1 += '.', s1 += v;
    s1 += '.';
    manacher1(s1, tmp);
    for(int i=1; i<=n; i++) p[i] = tmp[i*2-1]/2;
}
void sol()
{
    cin >> s;
    int n=s.length();
    manacher1(s, d1);
    manacher2(s, d2);
    s=" "+s;
    int l=-1, r=-1;
    int c1, c2;
    for (int i=1; i<=n; i++)
    {
        c1 = i-d1[i];
        c2 = i+d1[i];
        if (c2-c1+1 > r-l+1) l = c1, r = c2;
        c1 = i-d2[i];
        c2 = i+d2[i]-1;
        if (c1>=1 && c2<=n && c1<=c2 && c2-c1+1 > r-l+1) l=c1, r=c2;
    }
    cout << r-l+1;
}
signed main()
{
//    freopen("divisor.INP", "r", stdin);
//    freopen("divisor.OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin >> t;
    while(t--)
    {
        sol();
    }
}

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