oj.uz

Submission #292925

# Submission time Handle Problem Language Result Execution time Memory
292925 2020-09-07T14:50:23 Z Benq Monochrome Points (JOI20_monochrome) C++14
100 / 100
 32 ms 10260 KB 
#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double; 
using str = string; // yay python!

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

using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>; 
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>; 
using vpd = vector<pd>;

#define tcT template<class T
// ^ lol this makes everything look weird but I'll try it
tcT> using V = vector<T>; 
tcT, size_t SZ> using AR = array<T,SZ>; 

// pairs
#define mp make_pair
#define f first
#define s second

// vectors
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#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 trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 4e5+5;
const ll INF = 1e18; // not too close to LLONG_MAX
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

// helper funcs
constexpr int pct(int x) { return __builtin_popcount(x); } // # of bits set
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
ll half(ll x) { return fdiv(x,2); }

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

#define tcTU tcT, class U
tcTU> T fstTrue(T lo, T hi, U f) { 
	// note: if (lo+hi)/2 is used instead of half(lo+hi) 
	// then this will loop infinitely when lo=hi
	hi ++; assert(lo <= hi); // assuming f is increasing
	while (lo < hi) { // find first index such that f is true 
		T mid = half(lo+hi);
		f(mid) ? hi = mid : lo = mid+1; 
	} 
	return lo;
}
tcTU> T lstTrue(T lo, T hi, U f) {
	lo --; assert(lo <= hi); // assuming f is decreasing
	while (lo < hi) { // find first index such that f is true 
		T mid = half(lo+hi+1);
		f(mid) ? lo = mid : hi = mid-1;
	} 
	return lo;
}
tcT> void remDup(vector<T>& v) { // sort and remove duplicates
	sort(all(v)); v.erase(unique(all(v)),end(v)); }
tcTU> void erase(T& t, const U& u) { // don't erase
	auto it = t.find(u); assert(it != end(t));
	t.erase(u); } // element that doesn't exist from (multi)set

// INPUT
#define tcTUU tcT, class ...U
tcT> void re(complex<T>& c);
tcTU> void re(pair<T,U>& p);
tcT> void re(vector<T>& v);
tcT, size_t SZ> void re(AR<T,SZ>& a);

tcT> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
tcTUU> void re(T& t, U&... u) { re(t); re(u...); }

tcT> void re(complex<T>& c) { T a,b; re(a,b); c = {a,b}; }
tcTU> void re(pair<T,U>& p) { re(p.f,p.s); }
tcT> void re(vector<T>& x) { trav(a,x) re(a); }
tcT, size_t SZ> void re(AR<T,SZ>& x) { trav(a,x) re(a); }

// 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
}
tcT> str ts(complex<T> c) { 
	stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
	str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
	res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
	str res = ""; F0R(i,SZ) res += char('0'+b[i]);
	return res; }
tcTU> str ts(pair<T,U> p);
tcT> str ts(T v) { // containers with begin(), end()
	#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
}
tcTU> str ts(pair<T,U> p) {
	#ifdef LOCAL
		return "("+ts(p.f)+", "+ts(p.s)+")"; 
	#else
		return ts(p.f)+" "+ts(p.s);
	#endif
}

// OUTPUT
tcT> void pr(T x) { cout << ts(x); }
tcTUU> void pr(const T& t, const U&... u) { 
	pr(t); pr(u...); }
void ps() { pr("\n"); } // print w/ spaces
tcTUU> void ps(const T& t, const U&... u) { 
	pr(t); if (sizeof...(u)) pr(" "); ps(u...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
tcTUU> void DBG(const T& t, const U&... u) {
	cerr << ts(t); if (sizeof...(u)) cerr << ", ";
	DBG(u...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
	#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 setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str s = "") {
	unsyncIO();
	// cin.exceptions(cin.failbit); 
	// throws exception when do smth illegal
	// ex. try to read letter into int
	if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}

int N;
str S;
int oc[2];
int ind[MX];
int cumB[MX], cumW[MX];

int dif(int a, int b) {
	b -= a; if (b < 0) b += N;
	return b;
}

vi nexB, nexW;

vl ans;
void oops(int l, int r, int val) {
	assert(l <= r);
	if (l < 0) l += N, r += N;
	if (r >= N) {
		oops(l,N-1,val);
		oops(0,r-N,val);
	} else {
		assert(0 <= l && l <= r && r < N);
		ans[l] += val, ans[r+1] -= val;
		// FOR(i,l,r+1) ans[i] += val;
	}
}
void addRangeW(int st, int l, int r, int val) {
	ckmax(l,0), ckmin(r,2*N-1); if (l > r) return;
	int lo = l?cumW[l-1]:0, hi = cumW[r]-1;
	if (lo <= hi) oops(lo-st,hi-st,val);
	// FOR(i,l,r+1) if (S[i] == 'W') ans[dif(st,ind[i])] += val;
}
void addRangeB(int st, int l, int r, int val) {
	ckmax(l,0), ckmin(r,2*N-1); if (l > r) return;
	int lo = l?cumB[l-1]:0, hi = cumB[r]-1;
	if (lo <= hi) oops(st-hi,st-lo,val);
	// FOR(i,l,r+1) if (S[i] == 'B') ans[dif(ind[i],st)] += val;
}

vl getDif(int big) {
	ans = vl(N+1);
	F0R(i,2*N) {
		if (S[i] == 'B') {
			addRangeW(ind[i],i+1,i+big,-cumB[i]);
			addRangeW(ind[i],i+1-2*N,i+big-2*N,-cumB[i]+N);
		} else {
			addRangeB(ind[i],i-big,i-1,cumB[i]);
			addRangeB(ind[i],i-big+2*N,i-1+2*N,cumB[i]);
		}
	}
	FOR(i,1,N+1) ans[i] += ans[i-1];
	ans.pop_back();
	return ans;
}

int main() {
	setIO(); re(N,S);
	F0R(i,sz(S)) ind[i] = oc[S[i] == 'B']++;
	{
		int cur = 0;
		F0R(i,sz(S)) cumB[i] = (cur += S[i] == 'B');
	}
	{
		int cur = 0;
		F0R(i,sz(S)) cumW[i] = (cur += S[i] == 'W');
	}
	vl x = getDif(N);
	trav(t,S) if (t == 'B') t = 'W';
	else t = 'B';
	F0R(i,sz(S)) swap(cumB[i],cumW[i]);
	vl y = getDif(N-1);
	ll ret = 0;
	F0R(i,N) ckmax(ret,x[i]+y[(N-i)%N]);
	ps(ret);
	// F0R(i,N) ckmax(ret,ans[i]);
	// ps(ret);
	// you should actually read the stuff at the bottom
}

/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/

Compilation message

monochrome.cpp: In function 'void setIn(str)':
monochrome.cpp:185:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  185 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
monochrome.cpp: In function 'void setOut(str)':
monochrome.cpp:186:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  186 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct

Subtask #2
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 0 ms 384 KB Output is correct
16 Correct 1 ms 416 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 0 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 0 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 0 ms 384 KB Output is correct
25 Correct 0 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 0 ms 384 KB Output is correct
29 Correct 0 ms 384 KB Output is correct
30 Correct 0 ms 384 KB Output is correct
31 Correct 0 ms 384 KB Output is correct
32 Correct 0 ms 384 KB Output is correct
33 Correct 0 ms 384 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 0 ms 384 KB Output is correct
16 Correct 1 ms 416 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 0 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 0 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 0 ms 384 KB Output is correct
25 Correct 0 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 0 ms 384 KB Output is correct
29 Correct 0 ms 384 KB Output is correct
30 Correct 0 ms 384 KB Output is correct
31 Correct 0 ms 384 KB Output is correct
32 Correct 0 ms 384 KB Output is correct
33 Correct 0 ms 384 KB Output is correct
34 Correct 1 ms 512 KB Output is correct
35 Correct 1 ms 512 KB Output is correct
36 Correct 1 ms 512 KB Output is correct
37 Correct 1 ms 384 KB Output is correct
38 Correct 1 ms 512 KB Output is correct
39 Correct 1 ms 512 KB Output is correct
40 Correct 1 ms 512 KB Output is correct
41 Correct 1 ms 384 KB Output is correct
42 Correct 1 ms 512 KB Output is correct
43 Correct 1 ms 512 KB Output is correct
44 Correct 1 ms 512 KB Output is correct
45 Correct 1 ms 512 KB Output is correct
46 Correct 1 ms 512 KB Output is correct
47 Correct 1 ms 512 KB Output is correct
48 Correct 1 ms 512 KB Output is correct
49 Correct 1 ms 384 KB Output is correct
50 Correct 1 ms 512 KB Output is correct
51 Correct 1 ms 512 KB Output is correct
52 Correct 1 ms 512 KB Output is correct

Subtask #4
65.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 0 ms 384 KB Output is correct
16 Correct 1 ms 416 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 0 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 0 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 0 ms 384 KB Output is correct
25 Correct 0 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 0 ms 384 KB Output is correct
29 Correct 0 ms 384 KB Output is correct
30 Correct 0 ms 384 KB Output is correct
31 Correct 0 ms 384 KB Output is correct
32 Correct 0 ms 384 KB Output is correct
33 Correct 0 ms 384 KB Output is correct
34 Correct 1 ms 512 KB Output is correct
35 Correct 1 ms 512 KB Output is correct
36 Correct 1 ms 512 KB Output is correct
37 Correct 1 ms 384 KB Output is correct
38 Correct 1 ms 512 KB Output is correct
39 Correct 1 ms 512 KB Output is correct
40 Correct 1 ms 512 KB Output is correct
41 Correct 1 ms 384 KB Output is correct
42 Correct 1 ms 512 KB Output is correct
43 Correct 1 ms 512 KB Output is correct
44 Correct 1 ms 512 KB Output is correct
45 Correct 1 ms 512 KB Output is correct
46 Correct 1 ms 512 KB Output is correct
47 Correct 1 ms 512 KB Output is correct
48 Correct 1 ms 512 KB Output is correct
49 Correct 1 ms 384 KB Output is correct
50 Correct 1 ms 512 KB Output is correct
51 Correct 1 ms 512 KB Output is correct
52 Correct 1 ms 512 KB Output is correct
53 Correct 32 ms 10260 KB Output is correct
54 Correct 32 ms 10256 KB Output is correct
55 Correct 30 ms 9876 KB Output is correct
56 Correct 31 ms 9876 KB Output is correct
57 Correct 26 ms 10004 KB Output is correct
58 Correct 26 ms 10260 KB Output is correct
59 Correct 25 ms 9876 KB Output is correct
60 Correct 25 ms 9876 KB Output is correct
61 Correct 26 ms 10004 KB Output is correct
62 Correct 30 ms 10004 KB Output is correct
63 Correct 27 ms 9876 KB Output is correct
64 Correct 23 ms 9876 KB Output is correct
65 Correct 25 ms 9492 KB Output is correct
66 Correct 26 ms 9748 KB Output is correct
67 Correct 26 ms 9748 KB Output is correct
68 Correct 26 ms 9364 KB Output is correct
69 Correct 25 ms 10132 KB Output is correct
70 Correct 23 ms 9364 KB Output is correct
71 Correct 23 ms 10260 KB Output is correct
72 Correct 24 ms 10260 KB Output is correct
73 Correct 25 ms 10260 KB Output is correct