Submission #459610

#	Time	Username	Problem	Language	Result	Execution time	Memory
459610		nkato	Election (BOI18_election)	C++17	100 / 100	1452 ms	35764 KiB

election

#include <bits/stdc++.h>

using namespace std;

/////////////////////// MACROS ////////////////////////////////////////////
using ll = long long;
using ld = long double;
using db = double;
using str = string;

using pi = pair<int,int>;
using pl = pair<ll,ll>;

using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;


#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT, size_t SZ> using AR = array<T,SZ>;
tcTU> using P = pair<T,U>;
tcT> using PR = pair<T,T>;
tcTU> using omap = unordered_map<T, U>;
tcT> using oset = unordered_set<T>;
tcT> using mset = multiset<T>;

#define mp make_pair
#define fi first
#define se second

#define sz(x) int((x).size())
#define all(x) begin(x), end(x)
#define rall(x) x.rbegin(), x.rend()
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define ppb pop_back()
#define pb push_back
#define eb emplace_back
#define pf push_front

#define lb lower_bound
#define ub upper_bound

// LOOPS
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_, a)
#define each(a,x) for (auto& a: x)

/////////////////////// IMPORANT VARS /////////////////////////////////////

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INFL = 1e18+10;
const int INF = 1e9+10;
const ld PI = acos((ld)-1);
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1};
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;
tcT> using pql = priority_queue<T,vector<T>,less<T>>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define nl '\n'


// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;

// tcT> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; 
// #define ook order_of_key
// #define fbo find_by_order

// struct chash { 
// 	const uint64_t C = ll(2e18*PI)+71;
// 	const int RANDOM = rng();
// 	ll operator()(ll x) const {
// 		return __builtin_bswap64((x^RANDOM)*C); }
// };
// template<class K,class V> using um = unordered_map<K,V,chash>;
// template<class K,class V> using ht = gp_hash_table<K,V,chash>;
// template<class K,class V> V get(ht<K,V>& u, K x) {
// 	auto it = u.find(x); return it == end(u) ? 0 : it->s; }

tcT> bool ckmin(T& a, const T& b) {
	return b < a ? a = b, 1 : 0; } 
tcT> bool ckmax(T& a, const T& b) {
	return a < b ? a = b, 1 : 0; }

/////////////////////// TO_STRING /////////////////////////////////////////
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) {
	#ifdef LOCAL
		return b ? "true" : "false";
	#else
		return ts((int)b);
	#endif
}
tcTU> str ts(pair<T,U> p) {
	#ifdef LOCAL
		return "("+ts(p.fi)+", "+ts(p.se)+")";
	#else
		return ts(p.fi)+" "+ts(p.se);
	#endif
}

tcTU> str ts(V<pair<T, U>> v) {
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;
	#endif
}

tcT> str ts(T v) {
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;

	#endif
}

///////////////////////// DEBUG ///////////////////////////////////////////
#define tcTUU tcT, class ...U
void DBG() { cerr << "]" << endl; }
tcTUU> void DBG(const T& t, const U&... u) {
	cerr << ts(t); if (sizeof...(u)) cerr << ", ";
	DBG(u...); }
#ifdef LOCAL
	#define _GLIBCXX_DEBUG
	#define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
	#define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
		 << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
	#define dbg(...) 0
	#define chk(...) 0
#endif

///////////////////////// FILE I/O ////////////////////////////////////////
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setPrec() { cout << fixed << setprecision(15); }
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void setIO(str s = "") {
	unsyncIO(); setPrec();
	#ifndef LOCAL	
		if (sz(s)) setIn(s+".in"), setOut(s+".out"); // for USACO
	#endif
}

///////////////////////// TEMPLATE ABOVE //////////////////////////////////

// REMEMBER
// - Don't focus on only one approach
// - Read Problem Fully
// - Think of Edges Cases
// - Implement carefully

struct T {
	int pfx, sfx, tot, ans;

	T() {
		pfx = sfx = tot = ans = 0;
	}

	T(int p, int s, int t, int a) {
		pfx = p, sfx = s, tot = t, ans = a;
	}

	bool operator==(T a) {
		return (pfx == a.pfx && sfx == a.sfx
			 && tot == a.tot && ans == a.ans);
	}
};

struct Seg {
	V<T> seg; int N;
	const T ID = T();
	T comb(T a, T b) { 
		T c;

		c.tot = a.tot+b.tot;
		c.pfx = max(a.tot+b.pfx, a.pfx);
		c.sfx = max(b.tot+a.sfx, b.sfx);
		c.ans = max(max(a.ans+b.tot, b.ans+a.tot), a.pfx+b.sfx);
		return c;
	}

	void init(int _N) { N = 1; while(N < _N) N *= 2; seg.assign(2*N, ID); }

	void pull(int p) { seg[p] = comb(seg[2*p+1], seg[2*p+2]); }

	void build(const V<T>& A, int x, int lx, int rx) {
		if (rx-lx == 1) {
			if (lx < sz(A)) seg[x] = A[lx];
			return;
		}
		int m = (lx+rx)/2;
		build(A, x*2+1, lx, m);
		build(A, x*2+2, m, rx);
		pull(x);
	}

	void upd(int i, T v, int x, int lx, int rx) {
		if (rx-lx == 1) {
			seg[x] = v;
			return;
		}
		int m = (lx+rx)/2;
		if (i < m) upd(i, v, x*2+1, lx, m);
		else upd(i, v, x*2+2, m, rx);
		pull(x);
	}

	T qry(int l, int r, int x, int lx, int rx) {
		if (lx >= r || l >= rx) return ID;
		if (lx >= l && rx <= r) return seg[x];
		int m = (lx+rx)/2;
		T v1 = qry(l, r, 2*x+1, lx, m);
		T v2 = qry(l, r, 2*x+2, m, rx);
		return comb(v1, v2); 
	}
	
	void build(const V<T>& A) { build(A, 0, 0, N); }
	void upd(int i, T v) { upd(i, v, 0, 0, N); }
	T qry(int l, int r) { return qry(l, r, 0, 0, N); }
} st;

void solve() {
	int n; cin >> n;
	str s; cin >> s;
	V<T> a(n);
	F0R(i, n) {
		int v = (s[i] == 'C' ? -1 : 1);
		a[i] = T(max(0, v), max(0, v), v, max(0, v));
	}
	st.init(n);
	st.build(a);

	int q; cin >> q;
	rep(q) {
		int l, r; cin >> l >> r;
		--l;
		cout << st.qry(l, r).ans << endl;
	}
}

int main() {
	setIO(); 

	int TT = 1;
	// cin >> TT;

	rep(TT) solve();

	exit(0);
}

Compilation message (stderr)

election.cpp: In function 'void setIn(str)':
election.cpp:171:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  171 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
election.cpp: In function 'void setOut(str)':
election.cpp:172:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  172 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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