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Submission #939053

# Submission time Handle Problem Language Result Execution time Memory
939053 2024-03-06T04:33:59 Z vjudge1 Palindromic Partitions (CEOI17_palindromic) C++17
60 / 100
 1109 ms 8996 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 = 1e8 + 7, N = 1e5 + 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 <= mid; 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);
			}
		}
	}
	//cout << mid << endl;
	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:60:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   60 | 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
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3420 KB Output is correct
2 Correct 1 ms 3420 KB Output is correct
3 Correct 1 ms 3416 KB Output is correct
4 Correct 1 ms 3420 KB Output is correct
5 Correct 1 ms 3672 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3420 KB Output is correct
2 Correct 1 ms 3420 KB Output is correct
3 Correct 1 ms 3416 KB Output is correct
4 Correct 1 ms 3420 KB Output is correct
5 Correct 1 ms 3672 KB Output is correct
6 Correct 4 ms 3420 KB Output is correct
7 Correct 2 ms 3420 KB Output is correct
8 Correct 2 ms 3420 KB Output is correct
9 Correct 2 ms 3420 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3420 KB Output is correct
2 Correct 1 ms 3420 KB Output is correct
3 Correct 1 ms 3416 KB Output is correct
4 Correct 1 ms 3420 KB Output is correct
5 Correct 1 ms 3672 KB Output is correct
6 Correct 4 ms 3420 KB Output is correct
7 Correct 2 ms 3420 KB Output is correct
8 Correct 2 ms 3420 KB Output is correct
9 Correct 2 ms 3420 KB Output is correct
10 Correct 1109 ms 3572 KB Output is correct
11 Correct 321 ms 3560 KB Output is correct
12 Correct 613 ms 3552 KB Output is correct
13 Correct 442 ms 3524 KB Output is correct

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3420 KB Output is correct
2 Correct 1 ms 3420 KB Output is correct
3 Correct 1 ms 3416 KB Output is correct
4 Correct 1 ms 3420 KB Output is correct
5 Correct 1 ms 3672 KB Output is correct
6 Correct 4 ms 3420 KB Output is correct
7 Correct 2 ms 3420 KB Output is correct
8 Correct 2 ms 3420 KB Output is correct
9 Correct 2 ms 3420 KB Output is correct
10 Correct 1109 ms 3572 KB Output is correct
11 Correct 321 ms 3560 KB Output is correct
12 Correct 613 ms 3552 KB Output is correct
13 Correct 442 ms 3524 KB Output is correct
14 Runtime error 7 ms 8996 KB Execution killed with signal 11
15 Halted 0 ms 0 KB -