Submission #64864

#	Time	Username	Problem	Language	Result	Execution time	Memory
64864		Benq	Security Gate (JOI18_security_gate)	C++11	12 / 100	5074 ms	1012 KiB

securitygate

#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;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;

int n,ans;
string s;

/*void search(int ind, int mn, int mx, int mndif, int mxdif, int cur) {
    mn = min(mn,cur), mx = max(mx,cur);
    mxdif = max(mxdif,cur-mn);
    mndif = min(mndif,cur-mx);
    if (ind == sz(s)) {
        if (cur-2*mxdif <= 0 && cur-2*mndif >= 0) ans ++;
        return;
    }
    if (s[ind] != '(') search(ind+1,mn,mx,mndif,mxdif,cur+1);
    if (s[ind] != ')') search(ind+1,mn,mx,mndif,mxdif,cur+1);
}*/

bool ok(string s) {
    F0R(i,sz(s)+1) FOR(j,i,sz(s)+1) {
        int sum = 0;
        F0R(k,sz(s)) {
            if (k < i || k >= j) sum += 2*(s[k] == '(')-1;
            else sum += 2*(s[k] != '(')-1;
            if (sum < 0) break;
        }
        if (sum == 0) return 1;
    }
    return 0;
}

void search(int ind) {
    if (ind == sz(s)) {
        if (ok(s)) ans ++;
        return;
    }
    if (s[ind] == 'x') {
        s[ind] = '(';
        search(ind+1);
        s[ind] = ')';
        search(ind+1);
        s[ind] = 'x';
    } else search(ind+1);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n >> s;
    if (n % 2 == 1) {
        cout << 0;
        exit(0);
    }
    // search(0,0,0,0,0,0);
    search(0);
    cout << ans;
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 43
• Subtask 5: 0 / 27