Submission #961136

#	Time	Username	Problem	Language	Result	Execution time	Memory
961136		penguin133	Election (BOI18_election)	C++17	28 / 100	3036 ms	21252 KiB

election

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

char A[500005];
int n, q, died[500005], P[500005], S[500005];

//ans = min(min(P[l..i]) - P[l - 1] - S[r + 1] + min(S[i..r]) + (A[i] == 'T')) across all i

struct node{
	int s, e, m, val;
	node *l, *r;
	node(int _s, int _e){
		s = _s, e = _e, m = (s + e) >> 1;
		if(s != e)l = new node(s, m), r = new node(m+1, e);
		val = 0;
	}
	void upd(int p, int v){
		if(s == e)val = v;
		else{
			if(p <= m)l->upd(p, v);
			else r->upd(p, v);
			val = min(l->val, r->val);
		}
	}
	int qry(int a, int b){
		if(a == s && b == e)return val;
		if(b <= m)return l->qry(a, b);
		if(a > m)return r->qry(a, b);
		return min(l->qry(a, m), r->qry(m+1, b));
	}
}*root, *root2;

void solve(){
	cin >> n;
	for(int i = 1; i <= n; i++)cin >> A[i], P[i] = P[i - 1] + (A[i] == 'C' ? 1 : -1);
	for(int i = n; i >= 1; i--)S[i] = S[i + 1] + (A[i] == 'C' ? 1 : -1);
	cin >> q;
	root = new node(0, n + 1);
	root2 = new node(0, n + 1);
	for(int i = 0; i <= n + 1; i++){
		root->upd(i, P[i]);
		root2->upd(i, S[i]);
	}
	while(q--){
		int l, r; cin >> l >> r;
		int mn = 0, idx = l;
		for(int i = l; i <= r; i++){
			mn = min(mn, root->qry(l - 1, i) + root2->qry(i, r + 1) + (A[i] == 'T') - P[l - 1] - S[r + 1]);
		}
		
		cout << -mn << '\n';
	}
}

main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int tc = 1;
	//cin >> tc;
	for(int tc1=1;tc1<=tc;tc1++){
		// cout << "Case #" << tc1 << ": ";
		solve();
	}
}

Compilation message (stderr)

election.cpp: In function 'void solve()':
election.cpp:56:15: warning: unused variable 'idx' [-Wunused-variable]
   56 |   int mn = 0, idx = l;
      |               ^~~
election.cpp: At global scope:
election.cpp:65:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   65 | main(){
      | ^~~~

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