oj.uz

Submission #292895

# Submission time Handle Problem Language Result Execution time Memory
292895 2020-09-07T14:39:13 Z limabeans Monochrome Points (JOI20_monochrome) C++17
35 / 100
 2000 ms 36084 KB 
#include <bits/stdc++.h>
using namespace std;

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl





using ll = long long;

const ll mod = 1e9+7;
const int maxn = 1e6 + 5;




int n;
string s;
bool used[maxn];

template<typename T> struct bit1 {
    T add(T x, T y) {
	return x+y;
    }
    int n;
    vector<T> t;
    void init(int n) {
	this->n=n;
	t.resize(n+10);
    }
    T qry(int i) {
	T res=0;
	for (; i>0; i-=i&-i) res=add(res,t[i]);
	return res;
    }
    void upd(int i, T dx) {
	assert(i>=1 && i<=n);
	for (; i<=n; i+=i&-i) t[i]=add(t[i],dx);
    }
};


bool isect(pair<int,int> p, pair<int,int> q) {
    if (max(p.first,q.first) >= min(p.second,q.second)) return false;
    if (p.first>q.first) swap(p,q);
    if (p.first<=q.first && q.second<=p.second) return false;
    return true;
}

ll eval_brute(vector<pair<int,int>> v) {
    assert(int(v.size())==n/2);
    for (auto &p: v) {
	if (p.first>p.second) {
	    swap(p.first,p.second);
	}
    }
    ll res = 0;
    
    for (int i=0; i<n/2; i++) {
	for (int j=i+1; j<n/2; j++) {
	    if (isect(v[i],v[j])) res++;
	}
    }

    return res;

    
}


ll eval(vector<pair<int,int>> v) {
    assert(int(v.size())==n/2);
    int N = 0;
    vector<pair<int,int>> ev;
    map<int,int> close, open;
    for (auto &p: v) {
	if (p.first>p.second) {
	    swap(p.first,p.second);
	}
	p.first++;
	p.second++;
	N = max(N, p.second);
	ev.push_back({p.first,0});
	ev.push_back({p.second,1});
	close[p.first]=p.second;
	open[p.second]=p.first;
    }
			
    ll res = 0;
    bit1<ll> bit;
    bit.init(N);

    sort(ev.begin(), ev.end());
    
    for (auto p: ev) {
	if (p.second==0) {
	    bit.upd(p.first,+1);
	}
	if (p.second==1) {
	    bit.upd(open[p.first],-1);
	    int l = open[p.first];
	    int r = p.first;
	    assert(l<=r);
	    res += (bit.qry(r)-bit.qry(l-1));
	}
    }

    return res;
}

ll brute() {
    ll best=0;
    vector<int> B, W;
    for (int i=0; i<n; i++) {
	if (s[i]=='B') B.push_back(i); else W.push_back(i);
    }

    for (int iter=0; iter<n/2; iter++) {
	vector<pair<int,int>> v;
	for (int i=0; i<n/2; i++) {
	    v.push_back({B[i],W[i]});
	}
	ll res = eval(v);
	//cout<<iter<<": "<<res<<endl;
	//cout<<iter<<": "<<eval_brute(v)<<" "<<res<<endl;
	best = max(best, res);
	std::rotate(W.begin(), W.begin()+1, W.end());
    }
    
    return best;
}

vector<pair<int,int>> make(vector<int> B, vector<int> W) {
    vector<pair<int,int>> v;
    for (int i=0; i<n/2; i++) {
	int x=B[i];
	int y=W[i];
	if (x>y) swap(x,y);
	v.push_back({x,y});

    }
    return v;
}

vector<int> rota(vector<int> W, int r) {
    std::rotate(W.begin(), W.begin()+r, W.end());
    return W;
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);
    cin>>n>>s;
    n *= 2;

    // if (n<=10) {
    // 	out(brute());
    // }

    vector<int> B, W;
    for (int i=0; i<n; i++) {
	if (s[i]=='B') B.push_back(i); else W.push_back(i);
    }
    auto ivals = make(B, W);
    auto W1 = rota(W, 1);
    auto ivals1 = make(B, W1);


    ll best = eval(ivals);

    int lo = 0;
    int hi = n/2;

    // dips first
    if (eval(ivals) >= eval(ivals1)) {
	int L = 0;
	int R = n/2;
	while (R-L>1) {
	    int M = (L+R)/2;
	    auto w1 = rota(W,M);
	    auto w2 = rota(W,M+1);
	    ll tmp1 = eval(make(B,w1));
	    ll tmp2 = eval(make(B,w2));
	    best = max({best, tmp1, tmp2});
	    if (tmp1>=tmp2) {
		L = M;
	    } else {
		R = M;
	    }
	}

	lo = L+1;
    }

    // watch(lo);
    // watch(hi);

    while (hi-lo>1) {
	int mid=(lo+hi)/2;
	auto w1 = rota(W,mid);
	auto w2 = rota(W,mid+1);
	ll tmp1 = eval(make(B,w1));
	ll tmp2 = eval(make(B,w2));
	best = max({best, tmp1, tmp2});

	if (tmp1<=tmp2) {
	    lo = mid;
	} else {
	    hi = mid;
	}
    }

    // watch(brute());
    // assert(best==brute());
    cout<<best<<endl;
       
    return 0;
}

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 1 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 1 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 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 1 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 1 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 1 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 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 6 ms 384 KB Output is correct
15 Correct 6 ms 384 KB Output is correct
16 Correct 6 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 3 ms 384 KB Output is correct
20 Correct 3 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 3 ms 384 KB Output is correct
23 Correct 4 ms 384 KB Output is correct
24 Correct 3 ms 384 KB Output is correct
25 Correct 3 ms 384 KB Output is correct
26 Correct 5 ms 384 KB Output is correct
27 Correct 5 ms 384 KB Output is correct
28 Correct 3 ms 384 KB Output is correct
29 Correct 5 ms 384 KB Output is correct
30 Correct 3 ms 384 KB Output is correct
31 Correct 6 ms 384 KB Output is correct
32 Correct 6 ms 384 KB Output is correct
33 Correct 3 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 1 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 1 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 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 6 ms 384 KB Output is correct
15 Correct 6 ms 384 KB Output is correct
16 Correct 6 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 3 ms 384 KB Output is correct
20 Correct 3 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 3 ms 384 KB Output is correct
23 Correct 4 ms 384 KB Output is correct
24 Correct 3 ms 384 KB Output is correct
25 Correct 3 ms 384 KB Output is correct
26 Correct 5 ms 384 KB Output is correct
27 Correct 5 ms 384 KB Output is correct
28 Correct 3 ms 384 KB Output is correct
29 Correct 5 ms 384 KB Output is correct
30 Correct 3 ms 384 KB Output is correct
31 Correct 6 ms 384 KB Output is correct
32 Correct 6 ms 384 KB Output is correct
33 Correct 3 ms 384 KB Output is correct
34 Correct 51 ms 760 KB Output is correct
35 Correct 51 ms 640 KB Output is correct
36 Correct 27 ms 640 KB Output is correct
37 Correct 48 ms 640 KB Output is correct
38 Correct 24 ms 640 KB Output is correct
39 Correct 26 ms 740 KB Output is correct
40 Correct 27 ms 768 KB Output is correct
41 Correct 24 ms 640 KB Output is correct
42 Correct 27 ms 640 KB Output is correct
43 Correct 54 ms 748 KB Output is correct
44 Correct 45 ms 640 KB Output is correct
45 Correct 26 ms 640 KB Output is correct
46 Correct 27 ms 640 KB Output is correct
47 Correct 51 ms 760 KB Output is correct
48 Correct 51 ms 640 KB Output is correct
49 Correct 45 ms 640 KB Output is correct
50 Correct 48 ms 640 KB Output is correct
51 Correct 48 ms 640 KB Output is correct
52 Correct 26 ms 760 KB Output is correct

Subtask #4
0.0 / 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 1 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 1 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 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 6 ms 384 KB Output is correct
15 Correct 6 ms 384 KB Output is correct
16 Correct 6 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 3 ms 384 KB Output is correct
20 Correct 3 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 3 ms 384 KB Output is correct
23 Correct 4 ms 384 KB Output is correct
24 Correct 3 ms 384 KB Output is correct
25 Correct 3 ms 384 KB Output is correct
26 Correct 5 ms 384 KB Output is correct
27 Correct 5 ms 384 KB Output is correct
28 Correct 3 ms 384 KB Output is correct
29 Correct 5 ms 384 KB Output is correct
30 Correct 3 ms 384 KB Output is correct
31 Correct 6 ms 384 KB Output is correct
32 Correct 6 ms 384 KB Output is correct
33 Correct 3 ms 384 KB Output is correct
34 Correct 51 ms 760 KB Output is correct
35 Correct 51 ms 640 KB Output is correct
36 Correct 27 ms 640 KB Output is correct
37 Correct 48 ms 640 KB Output is correct
38 Correct 24 ms 640 KB Output is correct
39 Correct 26 ms 740 KB Output is correct
40 Correct 27 ms 768 KB Output is correct
41 Correct 24 ms 640 KB Output is correct
42 Correct 27 ms 640 KB Output is correct
43 Correct 54 ms 748 KB Output is correct
44 Correct 45 ms 640 KB Output is correct
45 Correct 26 ms 640 KB Output is correct
46 Correct 27 ms 640 KB Output is correct
47 Correct 51 ms 760 KB Output is correct
48 Correct 51 ms 640 KB Output is correct
49 Correct 45 ms 640 KB Output is correct
50 Correct 48 ms 640 KB Output is correct
51 Correct 48 ms 640 KB Output is correct
52 Correct 26 ms 760 KB Output is correct
53 Execution timed out 2096 ms 36084 KB Time limit exceeded
54 Halted 0 ms 0 KB -