Submission #674530

#	Time	Username	Problem	Language	Result	Execution time	Memory
674530		alexdd	Election (BOI18_election)	C++17	100 / 100	486 ms	29444 KiB

election

#pragma GCC optimize("O3,unroll-loops")
#include<bits/stdc++.h>
using namespace std;
struct node
{
    int max_pref;
    int max_suff;
    int sum;
    int qry;
};
node combine(node x, node y)
{
    node rez;
    rez.sum = x.sum + y.sum;
    rez.max_pref = max(x.max_pref, x.sum + y.max_pref);
    rez.max_suff = max(y.max_suff, y.sum + x.max_suff);
    rez.qry = max(x.max_pref + y.max_suff, max(x.qry + y.sum, y.qry + x.sum));
    return rez;
}
node aint[2100001];
int n;
int v[500001];
void build(int nod, int st, int dr)
{
    if(st==dr)
    {
        int x;
        if(v[st]==1) x=1;
        else x=0;
        aint[nod]={max(0,v[st]),max(0,v[st]),v[st],x};
        return;
    }
    int mij=(st+dr)/2;
    build(nod*2,st,mij);
    build(nod*2+1,mij+1,dr);
    aint[nod]=combine(aint[nod*2], aint[nod*2+1]);
}
node query(int nod, int st, int dr, int le, int ri)
{
    if(le>ri)
        return {0,0,0,0};
    if(le==st && dr==ri)
        return aint[nod];
    int mij=(st+dr)/2;
    return combine(query(nod*2,st,mij,le,min(mij,ri)),
                   query(nod*2+1,mij+1,dr,max(mij+1,le),ri));
}
signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);

    cin>>n;
    char ch;
    for(int i=1;i<=n;i++)
    {
        cin>>ch;
        if(ch=='T')
            v[i]=1;
        else
            v[i]=-1;
    }
    build(1,1,n);
    int q,l,r;
    node x;
    cin>>q;
    for(int i=0;i<q;i++)
    {
        cin>>l>>r;
        x=query(1,1,n,l,r);
        cout<<x.qry<<"\n";
    }
    return 0;
}
/**

*/

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