Submission #554524

#	Time	Username	Problem	Language	Result	Execution time	Memory
554524		Awerar	Three Friends (BOI14_friends)	C++14	100 / 100	70 ms	8496 KiB

friends

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <limits.h>
#include <math.h>
#include <chrono>
#include <queue>
#include <stack>
#include <algorithm>

using namespace std;

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

#define ll long long
#define vi vector<ll>
#define vvi vector<vi>
#define p2 pair<ll, ll>
#define p3 tuple<ll,ll,ll>
#define p4 vi
#define ip3 tuple<int,int,int>
#define ip4 tuple<int,int,int,int>
#define vp2 vector<p2>
#define vp3 vector<p3>
#define inf 2e9
#define linf 1e17

#define read(a) cin >> a
#define write(a) cout << (a) << "\n"
#define dread(type, a) type a; cin >> a
#define dread2(type, a, b) dread(type, a); dread(type, b)
#define dread3(type, a, b, c) dread2(type, a, b); dread(type, c)
#define dread4(type, a, b, c, d) dread3(type, a, b, c); dread(type, d)
#define dread5(type, a, b, c, d, e) dread4(type, a, b, c, d); dread(type, e)
#ifdef _DEBUG
#define deb __debugbreak();
#else
#define deb ;
#endif

#define rep(i, high) for (ll i = 0; i < high; i++)
#define repp(i, low, high) for (ll i = low; i < high; i++)
#define repe(i, container) for (auto& i : container)
#define per(i, high) for (ll i = high; i >= 0; i--)

#define readpush(type,vect) type temp; read(temp); vect.push_back(temp);
#define readvector(type, name, size) vector<type> name(size); rep(i,size) {dread(type,temp); name[i]=temp;}
#define readinsert(type,a) {type temp; read(temp); a.insert(temp);}
#define all(a) begin(a),end(a)
#define setcontains(set, x) (set.find(x) != set.end())
#define stringcontains(str, x) (str.find(x) != string::npos)
#define within(a, b, c, d) (a >= 0 && a < b && c >= 0 && c < d)

#define ceildiv(x,y) ((x + y - 1) / y)
#define fract(a) (a-floor(a))
#define sign(a) ((a>0) ? 1 : -1)

auto Start = chrono::high_resolution_clock::now();

inline void fast()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
}

#define NP "NOT POSSIBLE"
#define NU "NOT UNIQUE"

int main() {
    //fast();
    
    dread(int, n);
    dread(string, u);

    if(n % 2 == 0) {
        write(NP);
        return 0;
    }

    ll s_len = (u.size() - 1) / 2;

    //Assume wrong is in second
    string s1 = "";
    for(int i = 0; i < s_len; i++) {
        s1 += u[i];
    }

    bool found_wrong1 = false;
    bool valid1 = true;
    for(int i = 0; i < s_len; i++) {
        int k = i + s_len;
        if(found_wrong1) k++;

        if(s1[i] != u[k]) {
            if(found_wrong1 || u[k + 1] != s1[i]) {
                valid1 = false;
                break;
            }

            found_wrong1 = true;
        }
    }

    //if(!found_wrong1) valid1 = false;

    //Assume wrong is in first
    string s2 = "";
    for(int i = 0; i < s_len; i++) {
        s2 += u[i + s_len + 1];
    }

    bool found_wrong2 = false;
    bool valid2 = true;
    for(int i = 0; i < s_len; i++) {
        int k = i;
        if(found_wrong2) k++;

        if(s2[i] != u[k]) {
            if(found_wrong2 || u[k + 1] != s2[i]) {
                valid2 = false;
                break;
            }

            found_wrong2 = true;
        }
    }

    if(valid1 && valid2) {
        if(s1 == s2) write(s1);
        else write(NU);
    } else if(valid1) {
        write(s1);
    } else if (valid2) {
        write(s2);
    } else {
        write(NP);
    }
}

/*
7
ABXCABC

6
ABCDEF

9
ABABABABA

7
ABXCABD
*/

Compilation message (stderr)

friends.cpp:18: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   18 | #pragma GCC optimization ("O3")
      | 
friends.cpp:19: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   19 | #pragma GCC optimization ("unroll-loops")
      |

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