Submission #537670

#	Time	Username	Problem	Language	Result	Execution time	Memory
537670		zaneyu	Security Gate (JOI18_security_gate)	C++14	30 / 100	961 ms	332 KiB

securitygate

/*input
3
x))
*/
#include<bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<n;i++)
#define MNTO(x,y) x=min(x,y)
#define MXTO(x,y) x=max(x,y)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define ll long long
#define ld long double
#define sz(x) (int)x.size()
#define pii pair<ll,ll>
#define pdd pair<ld,ld>
#define f first
#define s second
#define pb push_back
#define ALL(x) x.begin(),x.end()
const int INF=0x3f3f3f3f;
const int maxn=100+5;
int pf[maxn],pm[maxn];
bool check(string s){
    int n=sz(s);
    int x=0;
    int mn=INF;
    REP1(i,n){
        if(s[i-1]=='(') ++x;
        else --x;
        pf[i]=x;
        MNTO(mn,pf[i]);
    }
    int r=0;
    for(int i=n;i>=0;i--){
        if(pf[i]<pf[n]){
            r=i;
            break;
        }
    }
    if(pf[n]==0 and mn==0){
        return true;
    }
    REP(i,n+2) pm[i]=0;
    for(int i=r;i>=0;i--){
        pm[i]=max(pm[i+1],pf[i]);
    }
    REP1(j,n){
        if(pf[j-1]<0) break;
        int mx=pm[j];
        for(int i=max(r,j);i<=n;i++){
            MXTO(mx,pf[i]);
            if(mx>pf[j-1]*2){
                break;
            }
            if((2*pf[j-1]-2*pf[i]+pf[n])==0){
                return true;
            }
        }
    }
    return false;
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int n;
    cin>>n;
    if(n%2){
        cout<<0;
        return 0;
    }
    string s;
    cin>>s;
    vector<int> v;
    REP(i,n){
        if(s[i]=='x') v.pb(i);
    }
    int ans=0;
    REP(i,(1<<sz(v))){
        string tmp=s;
        REP(j,sz(v)){
            if(i&(1<<j)) s[v[j]]='(';
            else s[v[j]]=')';
        }
        ans+=check(s);
        s=tmp;
    }
    cout<<ans;
}

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