oj.uz

Submission #939255

# Submission time Handle Problem Language Result Execution time Memory
939255 2024-03-06T07:33:33 Z vjudge1 Palindromic Partitions (CEOI17_palindromic) C++17
60 / 100
 10000 ms 42428 KB 
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#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 = 1e8 + 7, N = 1e6 + 100, inf = 1e9, mod2 = 1e9 + 7;

int pw[N], hsh[N], hsh2[N], pw2[N];

int get(int l, int r){
  return (((hsh[r]-hsh[l-1]+mod)%mod)*pw[N - r])%mod; 
}
int get2(int l, int r){
	return (((hsh2[r]-hsh2[l-1]+mod2)%mod2)*pw2[N - r])%mod2;
}
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;
		hsh2[i]=(hsh2[i-1]+((s[i]-'a'+1)*pw2[i-1])%mod2)%mod2;
	}
	
	vector <int> dp(n + 1, -inf);
	
	dp[0] = 0;
	int ans = 1;
	int mid = n / 2;
	for(int i = 1; i <= mid; i++){
		for(int j = i; j >= 1; j--){
			swap(i, j);
			if(get(n - j + 1,n - i + 1) == get(i, j) && get2(n - j + 1,n - i + 1) == get2(i, j)){
				dp[j] = max(dp[i - 1] + 2, dp[j]);
				ans = max(dp[j], ans);
				swap(i, j);
				break;
			}
			swap(i, j);
		}
	}
	
	for(int i = 0; i <= (n - 1) / 2; 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;
    pw2[0] = 1;
	for(int i=1;i<N;i++){
		pw[i]=(pw[i-1]*27)%mod;
		pw2[i] = (pw2[i - 1] * 31) % mod2;
	}
	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:66:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   66 | main(){
      | ^~~~
palindromic.cpp: In function 'void fp(std::string)':
palindromic.cpp:15:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:15:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 17244 KB Output is correct
2 Correct 7 ms 17292 KB Output is correct
3 Correct 7 ms 17244 KB Output is correct
4 Correct 7 ms 17276 KB Output is correct
5 Correct 7 ms 17244 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 17244 KB Output is correct
2 Correct 7 ms 17292 KB Output is correct
3 Correct 7 ms 17244 KB Output is correct
4 Correct 7 ms 17276 KB Output is correct
5 Correct 7 ms 17244 KB Output is correct
6 Correct 7 ms 17244 KB Output is correct
7 Correct 8 ms 17244 KB Output is correct
8 Correct 7 ms 17244 KB Output is correct
9 Correct 7 ms 17240 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 17244 KB Output is correct
2 Correct 7 ms 17292 KB Output is correct
3 Correct 7 ms 17244 KB Output is correct
4 Correct 7 ms 17276 KB Output is correct
5 Correct 7 ms 17244 KB Output is correct
6 Correct 7 ms 17244 KB Output is correct
7 Correct 8 ms 17244 KB Output is correct
8 Correct 7 ms 17244 KB Output is correct
9 Correct 7 ms 17240 KB Output is correct
10 Correct 17 ms 17500 KB Output is correct
11 Correct 327 ms 17584 KB Output is correct
12 Correct 43 ms 17500 KB Output is correct
13 Correct 11 ms 17500 KB Output is correct

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 17244 KB Output is correct
2 Correct 7 ms 17292 KB Output is correct
3 Correct 7 ms 17244 KB Output is correct
4 Correct 7 ms 17276 KB Output is correct
5 Correct 7 ms 17244 KB Output is correct
6 Correct 7 ms 17244 KB Output is correct
7 Correct 8 ms 17244 KB Output is correct
8 Correct 7 ms 17244 KB Output is correct
9 Correct 7 ms 17240 KB Output is correct
10 Correct 17 ms 17500 KB Output is correct
11 Correct 327 ms 17584 KB Output is correct
12 Correct 43 ms 17500 KB Output is correct
13 Correct 11 ms 17500 KB Output is correct
14 Correct 3903 ms 42428 KB Output is correct
15 Execution timed out 10004 ms 39760 KB Time limit exceeded
16 Halted 0 ms 0 KB -