Submission #89356

#	Time	Username	Problem	Language	Result	Execution time	Memory
89356		Tieuphong	Three Friends (BOI14_friends)	C++11	0 / 100	23 ms	19328 KiB

friends

/***************************************************************************/
/**********************  LANG TU HAO HOA  **********************************/
/***************************************************************************/
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define sz(x) ((int) x.size())
#define PB push_back
#define PF push_front
#define MP make_pair
#define ll long long
#define F first
#define S second
#define maxc 1000000007
#define MOD 1000000007
#define base 107
#define eps 1e-6
#define pi acos(-1)
#define N 2000006
#define task ""
#define remain(x) ((x > MOD) ? (x - MOD) : x)

using namespace std;

int n;

string s, ans[3];

int dem = 0;

string Check(int st1, int st2, int id)
{
    bool dd = 0;
    string res = "";
    for (int i = st1, j = st2; i < st2 && j <= n; i++, j++)
    {
        if (s[i] == s[j]) res.PB(s[i]);
            else
            {
                if (dd) break;
                if (id == 1) i--;
                    else j--;
                dd = 1;
                continue;
            }
    }
    if (res.length() != n/2) return "NOT";
    return res;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    //freopen(task".inp", "r", stdin);
    //freopen(task".out", "w", stdout);
    cin >> n >> s;
    if (n & 1 == 0) return cout << "NOT POSSIBLE", 0;
    s = "#" + s;
    //cout << s << '\n';
    ans[1] = Check(1, n/2+1, 1);
    ans[2] = Check(1, n/2+2, 2);
    //cout << ans[1] << ' ' << ans[2] << '\n';
    if (ans[1] == "NOT" && ans[2] == "NOT") return cout << "NOT POSSIBLE", 0;
    if (ans[1] == "NOT") return cout << ans[2], 0;
    if (ans[2] == "NOT") return cout << ans[1], 0;
    if (ans[1] == ans[2]) return cout << ans[1], 0;
    cout << "NOT UNIQUE";
    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'std::__cxx11::string Check(int, int, int)':
friends.cpp:48:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (res.length() != n/2) return "NOT";
         ~~~~~~~~~~~~~^~~~~~
friends.cpp: In function 'int main()':
friends.cpp:58:15: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     if (n & 1 == 0) return cout << "NOT POSSIBLE", 0;
             ~~^~~~

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