Submission #486483

#	Time	Username	Problem	Language	Result	Execution time	Memory
486483		MilosMilutinovic	Election (BOI18_election)	C++14	100 / 100	1206 ms	28224 KiB

election

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
const ll mod2=998244353;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=501000;
int n,q;
string s;

struct node {
	int pf,sf,s,f;
}nd[4*N];
node comb(node x,node y) {
	node ret;
	ret.pf=max(x.pf,x.s+y.pf);
	ret.sf=max(y.sf,y.s+x.sf);
	ret.s=x.s+y.s;
	ret.f=max({x.pf+y.sf,x.f+y.s,x.s+y.f});
	return ret;
}
void build(int p,int l,int r) {
	if (l==r) {
		if (s[l]=='T') {
			nd[p].pf=nd[p].sf=nd[p].s=nd[p].f=1;
		} else {
			nd[p].pf=nd[p].sf=nd[p].f=0;
			nd[p].s=-1;		
		}
	} else {
		int md=l+r>>1;
		build(p+p,l,md);
		build(p+p+1,md+1,r);
		nd[p]=comb(nd[p+p],nd[p+p+1]);
	}
}
node get(int p,int l,int r,int ql,int qr) {
	if (ql>r||qr<l) return {0,0,0,0};
	if (ql<=l&&r<=qr) return nd[p];
	int md=l+r>>1;
	return comb(get(p+p,l,md,ql,qr),get(p+p+1,md+1,r,ql,qr));
}

int main() {
	cin>>n;
	cin>>s;
	cin>>q;
	build(1,0,n-1);
	while (q--) {
		int l,r;
		cin>>l>>r;
		--l; --r;
		cout<<get(1,0,n-1,l,r).f<<"\n";
	}	
}

Compilation message (stderr)

election.cpp: In function 'void build(int, int, int)':
election.cpp:47:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |   int md=l+r>>1;
      |          ~^~
election.cpp: In function 'node get(int, int, int, int, int)':
election.cpp:56:10: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   56 |  int md=l+r>>1;
      |         ~^~

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