Submission #928937

#	Time	Username	Problem	Language	Result	Execution time	Memory
928937		FanOfWilliamLin	Election (BOI18_election)	C++17	100 / 100	596 ms	44388 KiB

election

#include <bits/stdc++.h>
using namespace std;
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <class T> using oset=tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define int long long
#define ll long long
#define ld long double
#define ar array
#define vt vector
#define pb push_back
#define pf push_front
#define all(v) v.begin(), v.end()
#define lla(v) v.rbegin(), v.rend()

ll FIRSTTRUE(function<bool(ll)> f, ll lb, ll rb) {
	while(lb<rb) {
		ll mb=(lb+rb)/2;
		f(mb)?rb=mb:lb=mb+1; 
	} 
	return lb;
}
ll LASTTRUE(function<bool(ll)> f, ll lb, ll rb) {
	while(lb<rb) {
		ll mb=(lb+rb+1)/2;
		f(mb)?lb=mb:rb=mb-1; 
	} 
	return lb;
}

const ll INF=1000000000000000000LL;
const ll MOD=1e9+7;
const ll M=(1ll<<61)-1;
//const ll MOD=998244353; //sometimes need to be used

mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
const ll base=uniform_int_distribution<ll>(0, M-1)(rng);

ll bpow(ll a, ll b, ll DOM) {
	a%=DOM;
	ll res=1;
	while(b>0) {
		if(b&1)
			res=res*a%DOM;
		a=a*a%DOM;
		b>>=1;
	}
	return res;
}

int gcd_x, gcd_y, gcd_d;

int gcd(int a, int b) {
	if (!b) {
        gcd_x=1;
        gcd_y=0;
        return a;
    }
    gcd_d=gcd(b, a%b);
	int tmp=gcd_x;
	gcd_x=gcd_y;
	gcd_y=tmp-(a/b)*gcd_y;
    return gcd_d;
}

ll floor_div(ll x, ll y) {
	assert(y!=0);
	if (y<0) {
		y=-y;
		x=-x;
	}
	if (x>=0) return x/y;
	return (x+1)/y-1;
}
ll ceil_div(ll x, ll y) {
	assert(y!=0);
	if (y<0) {
		y=-y;
		x=-x;
	}
	if (x<=0) {
		return x/y;
	}
	return (x-1)/y+1;
}

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};

const int mxN=5e5+1;
int n, q;
string s;

struct Nodes {
	int mx_pref, mx_suf;
	int sum;
	int ans;
} ST[1<<20];

// 1: Cap
// 0: Tony

Nodes combine(const Nodes& a, const Nodes& b) {
	Nodes res;
	res.mx_pref=max(a.mx_pref, a.sum+b.mx_pref);
	res.mx_suf=max(b.mx_suf, a.mx_suf+b.sum);
	res.sum=a.sum+b.sum;
	res.ans=max(max(a.ans+b.sum, a.sum+b.ans), a.mx_pref+b.mx_suf);
	return res;
}

void upd(int pos, bool val, int id=1, int l=1, int r=n) {
	if(pos<l||pos>r) {
		return;
	}
	if(l==r) {
		// +1: Tony
		// -1: Cap
		if(!val) {
			ST[id].mx_pref=1;
			ST[id].mx_suf=1;
			ST[id].sum=1;
			ST[id].ans=1;
		}
		else {
			ST[id].mx_pref=0;
			ST[id].mx_suf=0;
			ST[id].sum=-1;
			ST[id].ans=0;
		}
		return;
	}
	int mid=(l+r)/2;
	upd(pos, val, 2*id, l, mid);
	upd(pos, val, 2*id+1, mid+1, r);
	ST[id]=combine(ST[2*id], ST[2*id+1]);
}

Nodes qury(int u, int v, int id=1, int l=1, int r=n) {
	if(u>r||l>v) {
		return {0, 0, 0, 0};
	}
	if(l>=u&&v>=r) {
		return ST[id];
	}
	int mid=(l+r)/2;
	return combine(qury(u, v, 2*id, l, mid), qury(u, v, 2*id+1, mid+1, r));
}

void solve() {
	//solve here
	cin >> n;
	cin >> s;
	s=" "+s;
	for(int i=1; i<=n; ++i) {
		if(s[i]=='C') {
			upd(i, 1);
		}
		else {
			upd(i, 0);
		}
	}
	cin >> q;
	while(q--) {
		int l, r;
		cin >> l >> r;
		cout << qury(l, r).ans << "\n";
	}
}
 
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
 
	//freopen("template.inp", "r", stdin);
	//freopen("template.out", "w", stdout);	

	int TC=1;
	//cin >> TC;
	while(TC--) {
		solve();
	}
}

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