Submission #656221

#	Time	Username	Problem	Language	Result	Execution time	Memory
656221		Do_you_copy	Necklace (Subtask 1-3) (BOI19_necklace1)	C++17	85 / 85	232 ms	556 KiB

necklace

#include <bits/stdc++.h>
//#define int long long
#define fi first
#define se second
#define pb push_back
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
using ll = long long;
using ull = unsigned ll;
using ld = long double;
using pii = pair <int, int>;
using pil = pair <int, ll>;
using pli = pair <ll, int>;
using pll = pair <ll, ll>;
mt19937 Rand(chrono::steady_clock::now().time_since_epoch().count());
 
ll min(const ll &a, const ll &b){
    return (a < b) ? a : b;
}
 
ll max(const ll &a, const ll &b){
    return (a > b) ? a : b;
}
 
//const ll Mod = 1000000007;
//const ll Mod2 = 999999999989;
//only use when required
const int maxN = 1e5 + 1;
int n, m;
string rt;
void kmp(const string &s, vector <int> &p){
    int _n = s.length();
    p.resize(_n);
    p[0] = -1;
    for (int i = 1, j = -1; i < _n; ++i){
        while (j > -1 && s[j + 1] != s[i]){
            j = p[j];
        }
        if (s[j + 1] == s[i]) ++j;
        p[i] = j;
    }
}
 
tuple <int, int, int> get_ans(const string &s, const string &t, bool flag = 0){
    tuple <int, int, int> ans = {0, 0, 0};
    n = s.length(), m = t.length();
    for (int i = 0; i < n; ++i){
        vector <int> p1, p2;
        string s1 = s.substr(0, i);
        string s2 = s.substr(i, n - i);
        reverse(s1.begin(), s1.end());
        kmp(s1 + "#" + t, p1);
        kmp(s2 + "#" + rt, p2);
        for (int j = 0; j < m; ++j){
            ans = max(ans, {p1[i + j + 1] + p2[n + m - i - j - 1] + 2,
                      i - p1[i + j + 1] - 1,
                      flag ? m - j - 2 - p2[n + m - i - j - 1] : j - p1[i + j + 1]});
        }
    }
    return ans;
}
 
void Init(){
    string s, t;
    cin >> s >> t;
    rt = t;
    reverse(rt.begin(), rt.end());
    tuple <int, int, int> ans = get_ans(s, t);
    swap(t, rt);
    ans = max(ans, get_ans(s, t, 1));
    cout << get<0>(ans) << " " << get<1>(ans) << " " << get<2>(ans) << "\n";
}
 
#define debu
#define taskname "test"
signed main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        #ifdef debug
        freopen(taskname".out", "w", stdout);
        #endif
    }
    faster;
    ll tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
    if (fopen("timeout.txt", "r")){
        ofstream timeout("timeout.txt");
        timeout << 1000 * double(clock()) / CLOCKS_PER_SEC;
        #ifndef debug
        cerr << "\nTime elapsed: " << 1000 * double(clock()) / CLOCKS_PER_SEC << "ms\n";
        #endif
    }
}

Compilation message (stderr)

necklace.cpp: In function 'int main()':
necklace.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 40 / 40