Submission #45691

#	Time	Username	Problem	Language	Result	Execution time	Memory
45691		sorry_Benq	Palindromic Partitions (CEOI17_palindromic)	C++17	60 / 100	10102 ms	13800 KiB

palindromic

#include <bits/stdc++.h>
#define ll          long long
#define pb          push_back
#define mp          make_pair
#define pii         pair<int,int>
#define vi          vector<int>
#define all(a)      (a).begin(),(a).end()
#define F           first
#define S           second
#define sz(x)       (int)x.size()
#define hell        1000000007
#define endl        '\n'
using namespace std;
const int MAXN=1000005;
string s;
struct PalindromicTree{
    int N,cur;
    vector<map<int,int>> next;
    vector<int> link,start,len,diff,slink;
    PalindromicTree(): N(0),cur(0){
        node();
        len[0]=-1;
        node();
    }
    int node(){
        next.emplace_back();
        link.emplace_back(0);
        start.emplace_back(0);
        len.emplace_back(0);
        diff.emplace_back(0);
        slink.emplace_back(0);
        return N++;
    }
    void add_letter(int idx){
		//cout << s[idx] << endl;
        while(true){
            if(idx-len[cur]-1>=0 && s[idx-len[cur]-1]==s[idx])
                break;
            cur=link[cur];
        }
        if(next[cur].find(s[idx])!=next[cur].end()){
            cur=next[cur][s[idx]];
            return;
        }
        node();
        next[cur][s[idx]]=N-1;
        len[N-1]=len[cur]+2;
        start[N-1]=idx-len[N-1]+1;
        if(len[N-1]==1){
            link[N-1]=diff[N-1]=slink[N-1]=1;
            cur=N-1;
            return;
        }
        while(true){
            cur=link[cur];
            if(idx-len[cur]-1>=0 && s[idx-len[cur]-1]==s[idx])
                break;
        }
        link[N-1]=next[cur][s[idx]];
        diff[N-1]=len[N-1]-len[link[N-1]];
        if(diff[N-1]==diff[link[N-1]])
        	slink[N-1]=slink[link[N-1]];
        else
        	slink[N-1]=link[N-1];
        cur=N-1;
    }
};
ll dp[MAXN],sans[MAXN];
int main()
{
	int T; cin >> T;
	for (int testcase = 0; testcase < T; testcase++){
		string str;
		cin>>str;
		//cout << str << endl;
		PalindromicTree pt;
		int i,cur;
		s.clear();
		for(i=0;i<sz(str)/2;i++){
			s.pb(str[i]);
			s.pb(str[sz(str)-i-1]);
		}
		if (sz(str) % 2){
			s.pb(str[sz(str)/2]);
		}
		//cout << s.size() << endl;
		dp[0]=0;
		int res = 1;
		for(i=1;i<=sz(s);i++){
			dp[i] = -hell;
			pt.add_letter(i-1);
			//cout << i << ' ' << dp[i] << ' ' << pt.cur << endl;
			int cnt = 0;
			for(cur=pt.cur;cur>1;cur=pt.link[cur]){
				if (pt.len[cur] % 2 == 0){
					dp[i] = max(dp[i], dp[i - pt.len[cur]] + 2);
				}
			}
			int cur = dp[i];
			if (i != sz(s)) cur++;
			if (cur > res) res = cur;
		}
		cout << res << endl;
	}
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:93:8: warning: unused variable 'cnt' [-Wunused-variable]
    int cnt = 0;
        ^~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 40