Submission #746295

#	Time	Username	Problem	Language	Result	Execution time	Memory
746295		bgnbvnbv	Necklace (Subtask 1-3) (BOI19_necklace1)	C++14	85 / 85	605 ms	412 KiB

necklace

#include<bits/stdc++.h>
#define TASKNAME "codeforce"
#define pb push_back
#define pli pair<int,int>
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=3e4;
const ll inf=1e18;
const ll mod=1e9+7;
vector<int> prefix_function(string &s) {
    int n = (int)s.length();
    vector<int> pi(n);
    for (int i = 1; i < n; i++) {
        int j = pi[i-1];
        while (j > 0 && s[i] != s[j])
            j = pi[j-1];
        if (s[i] == s[j])
            j++;
        pi[i] = j;
    }
    return pi;
}
ll n;
string s,t;
ll cnt[maxN];
ll ans=0,id1=0,id2=0;
ll cal(bool tt)
{
    string a;
    for(int i=0;i<=n;i++)
    {
        a.clear();
        for(int j=i;j<n;j++)
        {
            a.pb(s[j]);
        }
        a.pb('#');
        for(int j=0;j<t.size();j++) a.pb(t[j]);
        auto vc=prefix_function(a);
        for(int j=0;j<=t.size();j++)
        {
            cnt[j]=0;
        }
        for(int j=0;j<=t.size();j++)
        {
            cnt[j]+=vc[j+n-i];
        }
        a.clear();
        for(int j=i-1;j>=0;j--)
        {
            a.pb(s[j]);
        }
        reverse(t.begin(),t.end());
        a.pb('#');
        for(int j=0;j<t.size();j++) a.pb(t[j]);
        vc=prefix_function(a);
        for(int j=0;j<=t.size();j++)
        {
            ll x=cnt[j]+vc[t.size()-j+i];
            if(ans<x)
            {
                ans=x;
                id1=i-vc[t.size()-j+i];
                if(tt)
                {
                    id1=id1+x-1;
                    id1=s.size()-id1-1;
                }
                id2=j-cnt[j];
            }
        }
        reverse(t.begin(),t.end());
    }
    return ans;
}
ll m;
void solve()
{
    cin >> s >> t;
    n=s.size();
    m=t.size();
    cal(0);
    reverse(s.begin(),s.end());
    cal(1);
    cout << ans<<'\n';
    cout << id1<<' '<<id2;
}
int main()
{
    fastio
    //freopen(TASKNAME".INP","r",stdin);
    //freopen(TASKNAME".OUT","w",stdout);
    solve();
}

Compilation message (stderr)

necklace.cpp: In function 'll cal(bool)':
necklace.cpp:41:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |         for(int j=0;j<t.size();j++) a.pb(t[j]);
      |                     ~^~~~~~~~~
necklace.cpp:43:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |         for(int j=0;j<=t.size();j++)
      |                     ~^~~~~~~~~~
necklace.cpp:47:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |         for(int j=0;j<=t.size();j++)
      |                     ~^~~~~~~~~~
necklace.cpp:58:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |         for(int j=0;j<t.size();j++) a.pb(t[j]);
      |                     ~^~~~~~~~~
necklace.cpp:60:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |         for(int j=0;j<=t.size();j++)
      |                     ~^~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 40 / 40