Submission #62519

#	Time	Username	Problem	Language	Result	Execution time	Memory
62519		Mamnoon_Siam	Three Friends (BOI14_friends)	C++17	100 / 100	113 ms	16788 KiB

friends

//#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <bits/stdc++.h>
// #include <bits/extc++.h>
using namespace std;

#define debug(s) cout << #s << " = " << s << endl
#define all(v) (v).begin(), (v).end()
#define KeepUnique(v) (v).erase( unique(all(v)), v.end() )
#define MEMSET(a, val) memset(a, val, sizeof (a))
#define PB push_back
#define endl '\n'
typedef long long ll;

inline int myrand(int l, int r) {
	int ret = rand(); ret <<= 15; ret ^= rand();
	if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
	return ret;
}

template <typename F, typename S>
ostream& operator << (ostream& os, const pair< F, S>& p) {
	return os<<"(" <<p.first<<", "<<p.second<<")"; }

typedef pair<int, int> ii;

template<typename T> using min_pq =
	std::priority_queue<T, vector<T>, greater<T> >;

//int dx[] = {-1, +0, +1, +0};
//int dy[] = {+0, +1, +0, -1};

bool can(string s, string p) {
	for(int i = 0; i < s.size(); i++) {
		if(s[i] != p[i]) {
			p.erase(p.begin() + i);
			return s == p;
		}
	} return true;
}

int32_t main () {
	// freopen("in", "r", stdin);
    int n; cin >> n;
    if(n % 2 == 0) {
    	cout << "NOT POSSIBLE" << endl;
    	return 0;
    }
    string s; cin >> s;
    string L = s.substr(0, (n >> 1));
    string LL = s.substr(0, (n >> 1) + 1);
    string R = s.substr((n >> 1) + 1, (n >> 1));
    string RR = s.substr((n >> 1), (n >> 1) + 1);
    assert(L + RR == s and LL + R == s);
    set<string> st;
    if(can(L, RR)) st.insert(L);
    if(can(R, LL)) st.insert(R);
    if(st.size() > 1) cout << "NOT UNIQUE" << endl;
    else if(can(L, RR)) cout << L << endl;
    else if(can(R, LL)) cout << R << endl;
    else cout << "NOT POSSIBLE" << endl;
}

Compilation message (stderr)

friends.cpp: In function 'int myrand(int, int)':
friends.cpp:18:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
  ^~
friends.cpp:18:26: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(ret < 0) ret = -ret; ret %= (r-l+1); ret += l;
                          ^~~
friends.cpp: In function 'bool can(std::__cxx11::string, std::__cxx11::string)':
friends.cpp:35:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < s.size(); i++) {
                 ~~^~~~~~~~~~

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