Submission #95982

#	Time	Username	Problem	Language	Result	Execution time	Memory
95982		luciocf	Three Friends (BOI14_friends)	C++14	0 / 100	33 ms	7196 KiB

friends

#include <bits/stdc++.h>
 
using namespace std;
 
const int maxn = 2e6+10;
 
int n;
 
string num, a, b;

int get_pref(void)
{
	int ind = -1;
	for (int i = 0; i < n/2; i++)
	{
		if (a[i] != b[i]) break;
		ind = i;
	}

	return ind;
}

int get_suf(void)
{
	int ind = (n+1)/2;
	for (int i = (n+1)/2-1; i >= 1; i--)
	{
		if (a[i] != b[i-1]) break;
		ind = i;
	}

	return ind;
}
 
int main(void)
{
	ios::sync_with_stdio(false); cin.tie(0);
 
	cin >> n >> num;
 
	if (n%2==0)
	{
		cout << "NOT POSSIBLE\n";
		return 0;
	}
 
	int ans = 0, add = n/2, possible = -1;
 
	bool ok = 1;
	for (int i = 0; i < add; i++)
		if (num[i] != num[i+add]) ok = 0;
 
	if (ok) ans++, possible = add;
 
	a = num.substr(0, n/2), b = num.substr(n/2, n/2+1);
 
	int pref = get_pref(), suf = get_suf();
 
	for (int i = 0; i < add; i++)
		if (pref >= i-1 && suf <= i+1) 
			ans++, possible = i;
 
	a = num.substr(0, n/2+1), b = num.substr(n/2+1, n/2);
 
	pref = get_pref(), suf = get_suf();
 
	for (int i = add; i < n; i++)
		if (pref >= (i-add) && suf <= (i-add)+2)
			ans++, possible = i;
 
	if (!ans) cout << "NOT POSSIBLE\n";
	else if (ans > 1) cout << "NOT UNIQUE\n";
	else
	{
		for (int i = 0, ind = 0; i < n && ind < add; i++)
			if (i != possible)
				cout << num[i], ind++;
		cout << "\n";
	}
}

• Subtask 1: 0 / 35
• Subtask 2: 0 / 65