Submission #861441

#	Time	Username	Problem	Language	Result	Execution time	Memory
861441		ReLice	Election (BOI18_election)	C++14	100 / 100	450 ms	78108 KiB

election

#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define sz size()
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define bc back()
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}
const ll inf=1e18+7;
const ll mod=998244353;
const ll N=5e5+7;
const ld eps=1e-9;
struct node{
	ll pref,suf,ans,sum;
	node operator +(node a){
		node b;
		b.sum=a.sum+sum;
		b.pref=max(pref,a.pref+sum);
		b.suf=max(a.suf,suf+a.sum);
		b.ans=max({0ll,sum+a.ans,a.sum+ans,pref+a.suf});
		return b;
	}
};
ll a[N];
vector <node> t(N*4);
void build(ll v,ll tl,ll tr){
	if(tl==tr){
		t[v].sum=a[tl];
		t[v].ans=t[v].pref=t[v].suf=max(a[tl],0ll);
		
		return;
	}
	ll tm=(tl+tr)/2;
	build(v*2,tl,tm);
	build(v*2+1,tm+1,tr);
	t[v]=t[v*2]+t[v*2+1];
}
node go(ll v,ll tl,ll tr,ll l,ll r){
	if(tl>r || tr<l)return {0ll,0ll,0ll,0ll};
	if(l<=tl && tr<=r){
		return t[v];
	}
	ll tm=(tl+tr)/2;
	node a=go(v*2,tl,tm,l,r),b=go(v*2+1,tm+1,tr,l,r);
	return a+b;
}
void solve(){
    ll i,q;
    ll n;
	cin>>n;
	str s;
	cin>>s;
	s=" "+s;
	for(i=1;i<=n;i++){
		if(s[i]=='C') a[i]=-1;
		else a[i]=1;
	}
	build(1,1,n);
	cin>>q;
	ll l,r;
	for(i=0;i<q;i++){
		cin>>l>>r;
		cout<<go(1,1,n,l,r).ans<<endl;
	}
}

signed main(){
    start();
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    ll t=1;
    //cin>>t;
    while(t--) solve();
}
/*
100
1 50 69 33  544
2 18 71 14 25 91 45
 
 
 
*/

Compilation message (stderr)

election.cpp: In function 'void fre(std::string)':
election.cpp:24:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:24:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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