Submission #1125821

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125821		Mikael639	Election (BOI18_election)	C++17	0 / 100	1 ms	320 KiB

election

#include <bits/stdc++.h>

#define fi first
#define se second

#define For(i, a, b) for (int i = (a); i <= (b); ++i)
#define ForD(i, a, b) for (int i = (a); i >= (b); --i)
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repD(i, n) for (int i = (n) - 1; i >= 0; --i)
#define coutE(x) {cout << x << '\n'; return;}
#define pb push_back
#define pf push_front

#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define bs binary_search
#define ub upper_bound
#define lb lower_bound

#define endl '\n'

#define db long double
#define ll long long
#define ii pair<int, int>
#define vi vector<int>
#define vii vector<ii>

using namespace std;

void file(string s){

    if (s.empty()) return;

    freopen((s + ".inp").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

template <class X, class Y>
	bool minimize(X &x, Y y){
		if (x > y){
			x = y;
			return 1;
		}
		
		return 0;
	}

template <class X, class Y>
	bool maximize(X &x, Y y){
		if (x < y){
			x = y;
			return 1;
		}
		
		return 0;
	}


mt19937_64 rng(time(0));

const int N = 1e6 + 5;

const int MOD = 1e9 + 7; //998244353;
const int INF = 1e9;
const long long LINF = 1e18;

const int dx[] = {1, 0, 0, -1};
const int dy[] = {0, 1, -1, 0};

int n, q, a[N];
char s[N];

struct Segment_Tree{
	struct Node{
		int pre, suf, sum;
	} st[4 * N];
	
	Node Merge(Node a, Node b){
		Node c;
		c.pre = max(a.pre, a.sum + b.pre);
		c.suf = max(b.suf, b.sum + a.suf);
		c.sum = a.sum + b.sum;
		return c;
	}
	
	void build(int id, int l, int r){
		if (l == r){
			st[id] = {max(a[l], 0), max(a[l], 0), a[l]};
			return;
		}
		
		int mid = (l + r) >> 1;
		build(id << 1, l, mid);
		build(id << 1 | 1, mid + 1, r);
		st[id] = Merge(st[id << 1], st[id << 1 | 1]);
	}
	
	Node get(int id, int l, int r, int u, int v){
		if (v < l || r < u) return {0, 0, 0};
		if (u <= l && r <= v) return st[id];
		
		int mid = (l + r) >> 1;
		return Merge(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
	}
} ST;

void solve(){

	cin >> n;
	cin >> (s + 1);
	For(i, 1, n) a[i] = (s[i] == 'C') ? -1 : 1;
	ST.build(1, 1, n);
	
	cin >> q;
	while (q--){
		int l, r; cin >> l >> r;
		Segment_Tree::Node x = ST.get(1, 1, n, l, r);
		cout << max(x.pre, x.suf) << endl;
	}
}


signed main(){

	ios_base::sync_with_stdio(0); 
	cin.tie(0); cout.tie(0);
	file("");

	int T = 1;
	//cin >> T;
	while (T--) solve();

	return 0;
}

Compilation message (stderr)

election.cpp: In function 'void file(std::string)':
election.cpp:34:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     freopen((s + ".inp").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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