Submission #716775

#	Time	Username	Problem	Language	Result	Execution time	Memory
716775		vjudge1	회문 (APIO14_palindrome)	C++17	8 / 100	1073 ms	11700 KiB

palindrome

#include <bits/stdc++.h>                     
  
#define ll long long 
#define pb push_back
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define sz(v) (int)v.size()
#define x first
#define y second
#define nl "\n"
  
using namespace std;
  
const int N = (int)1e3 + 7;
const int M = (int)2e6 + 5e5 + 7;
const ll MOD = (ll)1e9;                    
const int inf = (int)1e9 + 7;
const int B = (int)390;
const ll INF = (ll)1e18 + 7;
  
pair<int, int> dir[] = {{-1, 0}, {1, 0}, {0, 1}, {0, -1}};
 
bool bit(int mask, int i) {
    return (mask >> i & 1);
}
  
int sum(int x, int y) {
    x += y;
    if(x >= MOD) x -= MOD;
    return x;
}
  
int mult(int x, int y) {
    return 1ll * x * y % MOD;
}


vector<int> z_function (string s) {
	int n = sz(s);
	vector<int> z(n);
	for (int i = 1, l = 0, r = 0; i < n; ++i) {
		if (i <= r)
			z[i] = min(r - i + 1, z[i - l]);
		while (i + z[i] < n && s[z[i]] == s[i + z[i]])
			++z[i];
		if (i + z[i] - 1 > r)
			l = i,  r = i + z[i] - 1;
	}
	return z;
}

string s;
int cnt[N][N];
bool is[N][N];
                                 

void solve() {
	cin >> s;
	int ans = 0, n = sz(s);
	s = '#' + s;
	for(int i = 1; i <= n; ++i) {
		is[i][i] = 1;
		is[i][i - 1] = 1;
	}
	for(int len = 2; len <= n; ++len) {
		for(int i = 1; i <= n; ++i) {
			int j = i + len - 1;
			is[i][j] = (s[i] == s[j] && is[i + 1][j - 1]);
		}
	}
	for(int i = 1; i <= n; ++i) {
	    string cur;
		for(int j = i; j <= n; ++j) {
			cur += s[j];
			string t = cur;
			t += '#';
			t += s;
			vector<int> z = z_function(t);
			for(auto x : z) {
				if(x == j - i + 1) cnt[i][j]++;
			}	
		}
	}
	for(int i = 1; i <= n; ++i) {
		for(int j = i; j <= n; ++j) {
			if(!is[i][j]) continue;
			ans = max(ans, (j - i + 1) * cnt[i][j]);
		}
	}
	cout << ans << nl;
}       
 
  
signed main() {                   
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    //freopen("palindrome.in", "r", stdin);
    //freopen("palindrome.out", "w", stdout);    
    int test = 1;                       
    //cin >> test;
    for(int i = 1; i <= test; ++i) {
        //cout << "Case " << i << ":\n";
        solve();
    }
    return 0;
}                   
/*
possible causes of error :
* array  bounds
* int overflow
* special case (n == 1?)
* haven't clean something
* wrong N | M | inf | INF | MOD

* try to write brute force to find test
* don't waste time
* don't write bullshit
* solution is easy
*/

• Subtask 1: 8 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27