oj.uz

Submission #26170

# Submission time Handle Problem Language Result Execution time Memory
26170 2017-06-28T07:59:31 Z chpipis Three Friends (BOI14_friends) C++11
0 / 100
 89 ms 19596 KB 
#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pf push_front
#define iter(v, i) for (__typeof__((v).begin()) i = (v).begin(); i != (v).end(); i++)
#define fast_io_without_cstdio ios_base::sync_with_stdio(false), cin.tie(NULL)
#define all(v) (v).begin(), (v).end()
#define rep(i, s, e) for (int i = s; i < e; i++)

#ifdef __linux__
#define gc getchar_unlocked
#define pc putchar_unlocked
#else
#define gc getchar
#define pc putchar
#endif

#if __cplusplus <= 199711L
template<class BidirIt>
BidirIt prev(BidirIt it, typename iterator_traits<BidirIt>::difference_type n = 1) {
    advance(it, -n);
    return it;
}

template<class ForwardIt>
ForwardIt next(ForwardIt it, typename iterator_traits<ForwardIt>::difference_type n = 1) {
    advance(it, n);
    return it;
}
#endif

typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long double ldouble;

const double EPS = 1e-9;
const double PI = 3.141592653589793238462;

template<typename T>
inline T sq(T a) { return a * a; }

//#ifdef LOCAL_MACHINE
//#endif

const int MAXN = 2e6 + 5;
const int BASE = 29;
const int MOD = 1e9 + 7;

inline int mul_mod(int a, int b) {
    return a * 1LL * b % MOD;
}

inline void add_mod(int &a, int b) {
    a += b;
    if (a >= MOD) a -= MOD;
}

inline void sub_mod(int &a, int b) {
    a -= b;
    if (a < 0) a += MOD;
}

char str[MAXN];
int h[MAXN], bpow[MAXN];

int get_hash(int i, int j) {
    int ret = h[j];
    sub_mod(ret, mul_mod(h[i - 1], bpow[j - i + 1]));
    return ret;
}

int main() {
    bpow[0] = 1;
    for (int i = 1; i < MAXN; i++)
        bpow[i] = mul_mod(bpow[i - 1], BASE);
    //freopen("", "r", stdin);
    //freopen("", "w", stdout);
    int n;
    scanf("%d", &n);
    scanf("%s", str + 1);
    if (!(n & 1)) {
        puts("NOT POSSIBLE");
        return 0;
    }
    for (int i = 1; i <= n; i++) {
        h[i] = mul_mod(h[i - 1], BASE);
        add_mod(h[i], str[i] - 'A' + 1);
    }
    int ans = -1, cnt = 0;
    for (int i = 1; i <= n; i++) {
        int left, right;
        if (i <= (n / 2) + 1) {
            left = get_hash(1, i - 1);
            left = mul_mod(left, bpow[(n / 2) - (i - 1)]);
            add_mod(left, get_hash(i + 1, i + 1 + (n / 2) - (i - 1) - 1));

            right = get_hash(n - (n / 2) + 1, n);
        } else {
            left = get_hash(1, n / 2);

            int len = n - (i + 1) + 1;

            right = get_hash((n / 2) + 1, (n / 2) + 1 + (n / 2) - len - 1);
            right = mul_mod(right, bpow[len]);
            add_mod(right, get_hash(i + 1, n));
        }
        if (left == right) {
            cnt++;
            ans = i;
            //printf("I can replace char at pos %d\n", i);
        }
    }
    if (cnt > 1)
        puts("NOT UNIQUE");
    else if (cnt == 0)
        puts("NOT POSSIBLE");
    else {
        for (int i = 1, c = 0; c < (n / 2); i++) {
            if (ans == i) continue;
            c++;
            pc(str[i]);
        }
        pc('\n');
    }
    return 0;
}

Compilation message

friends.cpp: In function 'int main()':
friends.cpp:86:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
                    ^
friends.cpp:87:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s", str + 1);
                         ^

Subtask #1
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 19596 KB Output is correct
2 Correct 9 ms 19596 KB Output is correct
3 Correct 16 ms 19596 KB Output is correct
4 Correct 16 ms 19596 KB Output is correct
5 Correct 16 ms 19596 KB Output is correct
6 Correct 13 ms 19596 KB Output is correct
7 Correct 9 ms 19596 KB Output is correct
8 Correct 6 ms 19596 KB Output is correct
9 Correct 16 ms 19596 KB Output is correct
10 Correct 16 ms 19596 KB Output is correct
11 Correct 6 ms 19596 KB Output is correct
12 Correct 13 ms 19596 KB Output is correct
13 Correct 23 ms 19596 KB Output is correct
14 Correct 9 ms 19596 KB Output is correct
15 Correct 13 ms 19596 KB Output is correct
16 Correct 13 ms 19596 KB Output is correct
17 Correct 13 ms 19596 KB Output is correct
18 Correct 16 ms 19596 KB Output is correct
19 Correct 9 ms 19596 KB Output is correct
20 Correct 9 ms 19596 KB Output is correct
21 Correct 16 ms 19596 KB Output is correct
22 Correct 13 ms 19596 KB Output is correct
23 Correct 9 ms 19596 KB Output is correct
24 Correct 9 ms 19596 KB Output is correct
25 Correct 16 ms 19596 KB Output is correct
26 Correct 6 ms 19596 KB Output is correct
27 Correct 13 ms 19596 KB Output is correct
28 Correct 13 ms 19596 KB Output is correct
29 Correct 13 ms 19596 KB Output is correct
30 Correct 13 ms 19596 KB Output is correct
31 Correct 16 ms 19596 KB Output is correct
32 Correct 13 ms 19596 KB Output is correct
33 Correct 13 ms 19596 KB Output is correct
34 Correct 6 ms 19596 KB Output is correct
35 Correct 16 ms 19596 KB Output is correct
36 Correct 13 ms 19596 KB Output is correct
37 Correct 9 ms 19596 KB Output is correct
38 Correct 9 ms 19596 KB Output is correct
39 Correct 9 ms 19596 KB Output is correct
40 Correct 16 ms 19596 KB Output is correct
41 Correct 19 ms 19596 KB Output is correct
42 Correct 13 ms 19596 KB Output is correct
43 Correct 16 ms 19596 KB Output is correct
44 Correct 16 ms 19596 KB Output is correct
45 Correct 9 ms 19596 KB Output is correct
46 Correct 9 ms 19596 KB Output is correct
47 Correct 13 ms 19596 KB Output is correct
48 Correct 16 ms 19596 KB Output is correct
49 Correct 9 ms 19596 KB Output is correct
50 Incorrect 13 ms 19596 KB Output isn't correct
51 Halted 0 ms 0 KB -

Subtask #2
0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 76 ms 19596 KB Output is correct
2 Correct 73 ms 19596 KB Output is correct
3 Correct 69 ms 19596 KB Output is correct
4 Correct 79 ms 19596 KB Output is correct
5 Incorrect 89 ms 19596 KB Output isn't correct
6 Halted 0 ms 0 KB -