Submission #63145

# Submission time Handle Problem Language Result Execution time Memory
63145 2018-08-01T00:02:47 Z qkxwsm Three Friends (BOI14_friends) C++17
100 / 100
121 ms 40768 KB
/*
PROG: source
LANG: C++11
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
*/
#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 <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
        int operator()(int x) const
        {
                x ^= (x >> 20) ^ (x >> 12);
                return x ^ (x >> 7) ^ (x >> 4);
        }
        int operator()(long long x) const
        {
                return x ^ (x >> 32);
        }
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using hashtable = gp_hash_table<T, U, chash>;

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
        {
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
template<class T, class U>
T normalize(T x, U mod = 1000000007)
{
	return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
	return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
	return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 2000013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N;
int arr[MAXN];
ll pw[MAXN];
ll pref[MAXN];
ll go[MAXN];
int res = -1;
ll ha1, ha2;
bool ok[2];

ll getpw(ll a, ll e, ll mod)
{
        if (e == 1)
        {
                return a;
        }
        ll was = getpw(a, e / 2, mod);
        if (e % 2)
        {
                return was * was % mod * a % mod;
        }
        else
        {
                return was * was % mod;
        }
}
ll modinv(ll a, ll mod)
{
        return getpw(a, mod - 2, mod);
}
ll gethash(int l, int r)
{
        ll res = {pref[r + 1] - pref[l] * pw[r - l + 1]};
        res = normalize(res, INF);
        return res;
}

int32_t main()
{
	// ios_base::sync_with_stdio(0);
	srand(time(0));
	//	cout << fixed << setprecision(10);
	//	cerr << fixed << setprecision(10);
	if (fopen("input.in", "r"))
	{
		freopen ("input.in", "r", stdin);
		freopen ("output.out", "w", stdout);
	}
        // N = 1999999;
        readi(N);
        if (N % 2 == 0)
        {
                puts("NOT POSSIBLE\n");
                return 0;
        }
        for (int i = 0; i < N; i++)
        {
                char c = getchar();
                // char c = 'A';
                arr[i] = c - 'A' + 1;
        }
        pw[0] = 1;
        for (int i = 1; i <= N; i++)
        {
                pw[i] = pw[i - 1] * CO;
                pw[i] %= INF;
        }
        pref[0] = 0;
        for (int i = 0; i < N; i++)
        {
                pref[i + 1] = pref[i] * CO + arr[i];
                pref[i + 1] %= INF;
        }
        ha1 = gethash(0, (N / 2) - 1);
        ha1 *= pw[N / 2] + 1; ha1 %= INF;
        ha2 = gethash((N + 1) / 2, N - 1);
        ha2 *= pw[N / 2] + 1; ha2 %= INF;
        for (int i = 0; i < N; i++)
        {
                //remove i
                ll cur = (gethash(0, i - 1) * pw[N - i - 1] + gethash(i + 1, N - 1)) % INF;
                if (cur == ha1)
                {
                        ok[0] = true;
                }
                if (cur == ha2)
                {
                        ok[1] = true;
                }
        }
        if (!ok[0] && !ok[1])
        {
                puts("NOT POSSIBLE");
                return 0;
        }
        if (ok[0] && ok[1])
        {
                if (ha1 != ha2)
                {
                        puts("NOT UNIQUE");
                        return 0;
                }
        }
        if (ok[0])
        {
                for (int i = 0; i < (N / 2); i++)
                {
                        putchar((arr[i] + 'A' - 1));
                }
        }
        else
        {
                for (int i = (N + 1) / 2; i < N; i++)
                {
                        putchar((arr[i] + 'A' - 1));
                }
        }
        putchar('\n');
	// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Compilation message

friends.cpp: In function 'int32_t main()':
friends.cpp:189:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("input.in", "r", stdin);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
friends.cpp:190:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("output.out", "w", stdout);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 2 ms 380 KB Output is correct
2 Correct 3 ms 492 KB Output is correct
3 Correct 4 ms 492 KB Output is correct
4 Correct 3 ms 548 KB Output is correct
5 Correct 2 ms 548 KB Output is correct
6 Correct 2 ms 604 KB Output is correct
7 Correct 3 ms 604 KB Output is correct
8 Correct 2 ms 604 KB Output is correct
9 Correct 3 ms 604 KB Output is correct
10 Correct 3 ms 604 KB Output is correct
11 Correct 3 ms 604 KB Output is correct
12 Correct 3 ms 604 KB Output is correct
13 Correct 3 ms 604 KB Output is correct
14 Correct 4 ms 604 KB Output is correct
15 Correct 3 ms 624 KB Output is correct
16 Correct 3 ms 624 KB Output is correct
17 Correct 4 ms 624 KB Output is correct
18 Correct 3 ms 624 KB Output is correct
19 Correct 2 ms 624 KB Output is correct
20 Correct 2 ms 624 KB Output is correct
21 Correct 2 ms 624 KB Output is correct
22 Correct 3 ms 624 KB Output is correct
23 Correct 2 ms 624 KB Output is correct
24 Correct 3 ms 624 KB Output is correct
25 Correct 4 ms 624 KB Output is correct
26 Correct 3 ms 624 KB Output is correct
27 Correct 3 ms 624 KB Output is correct
28 Correct 3 ms 624 KB Output is correct
29 Correct 2 ms 624 KB Output is correct
30 Correct 3 ms 624 KB Output is correct
31 Correct 3 ms 624 KB Output is correct
32 Correct 2 ms 624 KB Output is correct
33 Correct 3 ms 624 KB Output is correct
34 Correct 2 ms 624 KB Output is correct
35 Correct 2 ms 728 KB Output is correct
36 Correct 2 ms 748 KB Output is correct
37 Correct 2 ms 748 KB Output is correct
38 Correct 2 ms 748 KB Output is correct
39 Correct 3 ms 748 KB Output is correct
40 Correct 3 ms 748 KB Output is correct
41 Correct 2 ms 748 KB Output is correct
42 Correct 3 ms 748 KB Output is correct
43 Correct 3 ms 748 KB Output is correct
44 Correct 2 ms 748 KB Output is correct
45 Correct 2 ms 748 KB Output is correct
46 Correct 3 ms 748 KB Output is correct
47 Correct 2 ms 748 KB Output is correct
48 Correct 3 ms 748 KB Output is correct
49 Correct 2 ms 748 KB Output is correct
50 Correct 3 ms 748 KB Output is correct
51 Correct 3 ms 748 KB Output is correct
52 Correct 3 ms 748 KB Output is correct
53 Correct 3 ms 748 KB Output is correct
54 Correct 2 ms 748 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 114 ms 40660 KB Output is correct
2 Correct 113 ms 40716 KB Output is correct
3 Correct 112 ms 40768 KB Output is correct
4 Correct 116 ms 40768 KB Output is correct
5 Correct 121 ms 40768 KB Output is correct
6 Correct 4 ms 40768 KB Output is correct
7 Correct 113 ms 40768 KB Output is correct
8 Correct 87 ms 40768 KB Output is correct
9 Correct 94 ms 40768 KB Output is correct
10 Correct 108 ms 40768 KB Output is correct
11 Correct 79 ms 40768 KB Output is correct
12 Correct 2 ms 40768 KB Output is correct
13 Correct 3 ms 40768 KB Output is correct
14 Correct 2 ms 40768 KB Output is correct
15 Correct 2 ms 40768 KB Output is correct
16 Correct 3 ms 40768 KB Output is correct
17 Correct 2 ms 40768 KB Output is correct
18 Correct 2 ms 40768 KB Output is correct
19 Correct 2 ms 40768 KB Output is correct
20 Correct 4 ms 40768 KB Output is correct
21 Correct 3 ms 40768 KB Output is correct
22 Correct 3 ms 40768 KB Output is correct
23 Correct 2 ms 40768 KB Output is correct
24 Correct 3 ms 40768 KB Output is correct
25 Correct 3 ms 40768 KB Output is correct
26 Correct 3 ms 40768 KB Output is correct
27 Correct 3 ms 40768 KB Output is correct
28 Correct 3 ms 40768 KB Output is correct
29 Correct 2 ms 40768 KB Output is correct
30 Correct 2 ms 40768 KB Output is correct
31 Correct 0 ms 40768 KB Output is correct
32 Correct 3 ms 40768 KB Output is correct
33 Correct 2 ms 40768 KB Output is correct
34 Correct 2 ms 40768 KB Output is correct
35 Correct 2 ms 40768 KB Output is correct
36 Correct 2 ms 40768 KB Output is correct
37 Correct 2 ms 40768 KB Output is correct
38 Correct 2 ms 40768 KB Output is correct
39 Correct 3 ms 40768 KB Output is correct
40 Correct 2 ms 40768 KB Output is correct
41 Correct 2 ms 40768 KB Output is correct
42 Correct 2 ms 40768 KB Output is correct
43 Correct 2 ms 40768 KB Output is correct
44 Correct 3 ms 40768 KB Output is correct
45 Correct 2 ms 40768 KB Output is correct
46 Correct 3 ms 40768 KB Output is correct
47 Correct 2 ms 40768 KB Output is correct
48 Correct 3 ms 40768 KB Output is correct
49 Correct 2 ms 40768 KB Output is correct
50 Correct 2 ms 40768 KB Output is correct
51 Correct 3 ms 40768 KB Output is correct
52 Correct 3 ms 40768 KB Output is correct
53 Correct 2 ms 40768 KB Output is correct
54 Correct 3 ms 40768 KB Output is correct