oj.uz

Submission #939044

# Submission time Handle Problem Language Result Execution time Memory
939044 2024-03-06T04:17:37 Z vjudge1 Palindromic Partitions (CEOI17_palindromic) C++17
0 / 100
 1 ms 1112 KB 
#include <bits/stdc++.h>
 
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define int long long
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
 
using namespace std;

void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);} 
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int mod = 1e9 + 7, N = 1e5 + 100, inf = 1e9;

int pw[N], hsh[N];

int get(int l, int r){
  return (((hsh[r]-hsh[l-1]+mod)%mod)*pw[N - r])%mod;
}

void solve(){
	string s;
	cin >> s;
	int n = s.size();
	s = ' ' + s;
	
	for(int i= 1; i <= n;i++){
		hsh[i]=(hsh[i-1]+((s[i]-'a'+1)*pw[i-1])%mod)%mod;
	}
	
	vector <int> dp(n + 1, -inf);
	
	dp[0] = 0;
	
	int mid = (n - 1) / 2;
	for(int i = 1; i <= mid; i++){
		for(int j = i; j <= mid; j++){
			if(get(n - j + 1,n - i + 1) == get(i, j)){
				dp[j] = max(dp[i - 1] + 2, dp[j]);
			}
		}
	}
	int ans = 0;
	for(int i = 0; i <= mid ; i++){
		ans = max(dp[i] + 1, ans);
	}
	cout << ans << endl;
}
 
main(){
	iostream::sync_with_stdio(false);	
    cin.tie(nullptr);
    cout.tie(nullptr);
    pw[0]=1;
	for(int i=1;i<N;i++){
		pw[i]=(pw[i-1]*27)%mod;
	}
	int t;
	cin >> t;
	while(t--)
		solve();
}	
/*
 * Before implementing the problem:
	
	Do I understand the problem correctly?
	Which places are tricky? What do I need to remember to implement them correctly?
	Which place is the heaviest by implementation? Can I do it simpler?
	Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
	----------------------------------
	If not AC:
 
	Did you remember to do everything to handle the tricky places you thought about before?
	Is the solution correct?
	Do I understand the problem correctly?
	----------------------------------
	If you have a test on which the solution gives wrong answer:
 
	Is the solution doing what it was supposed to do?
	Is the problem in the code or in the idea?
*/

Compilation message

palindromic.cpp:55:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main(){
      | ^~~~
palindromic.cpp: In function 'void fp(std::string)':
palindromic.cpp:13:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:13:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 1112 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 1112 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 1112 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 1112 KB Output isn't correct
2 Halted 0 ms 0 KB -