Submission #852913

#	Time	Username	Problem	Language	Result	Execution time	Memory
852913		Abito	Election (BOI18_election)	C++17	0 / 100	4 ms	31836 KiB

election

#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
//#define int long long
#define y1 YONE
typedef unsigned long long ull;
using namespace std;
const int N=5e5+5;
int n,q,a[N],st[25][N],lg[N],p[N],ans[N],l[N],r[N],ct[N];
void build(){
    for (int i=1;i<=n;i++) st[0][i]=p[i];
    for (int i=1;i<25;i++){
        for (int j=1;j+(1<<i)<=n+1;j++){
            st[i][j]=min(st[i-1][j],st[i-1][j+(1<<(i-1))]);
        }
    }return;
}
int query(int l,int r){
    int i=lg[r-l+1];
    return min(st[i][l],st[i][r-(1<<i)+1]);
}
int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    for (int i=2;i<N;i++) lg[i]=lg[i/2]+1;
    cin>>n;
    for (int i=1;i<=n;i++){
        char c;cin>>c;
        if (c=='C') a[i]=1;
        else a[i]=-1;
        p[i]=a[i]+p[i-1];
        ct[i]=ct[i-1]+bool(c=='T');
    }build();
    cin>>q;
    for (int i=1;i<=q;i++){
        cin>>l[i]>>r[i];
        ans[i]=max(0,-(query(l[i],r[i])-p[l[i]-1]));
        int L=l[i],R=r[i],mid,x;
        while (L<=R){
            //cout<<L<<' '<<R<<endl;
            mid=(L+R)/2;
            if (ct[mid]-ct[l[i]-1]>=ans[i]){
                x=mid;
                R=mid-1;
            }else L=mid+1;
        }l[i]=x+1;
        //cout<<l[i]<<' '<<r[i]<<endl;
    }
    for (int i=n;i;i--) p[i]=p[i+1]+a[i];
    build();
    for (int i=1;i<=q;i++){
        if (l[i]>r[i]) continue;
        ans[i]+=max(0,p[r[i]+1]-query(l[i],r[i]));
    }
    for (int i=1;i<=q;i++) cout<<ans[i]<<endl;
    return 0;
}

Compilation message (stderr)

election.cpp: In function 'int32_t main()':
election.cpp:52:16: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |         }l[i]=x+1;
      |               ~^~

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18