oj.uz

Submission #154820

# Submission time Handle Problem Language Result Execution time Memory
154820 2019-09-25T01:44:53 Z aer0park None (KOI16_dist) C++14
100 / 100
 419 ms 3484 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll, ll> p;

struct Star{
	ll x, y, dx, dy;
	void get(){
		cin >> x >> y >> dx >> dy;
	}
};

int n, t;
vector<Star> v;
vector<p> arr;

int ccw(p a, p b, p c){
	ll res = (a.first*b.second) + (b.first*c.second) + (c.first*a.second);
	res -= (b.first*a.second) + (c.first*b.second) + (a.first*c.second);
	if(res > 0) return 1;
	if(res) return -1;
	return 0;
}

ll dist(p a, p b){
	ll dx = a.first - b.first;
	ll dy = a.second - b.second;
	return dx*dx + dy*dy;
}

bool chk(p s, p e, p ss, p ee){
	p t = {e.first - s.first, e.second - s.second};
	p tt = {ee.first - ss.first, ee.second - ss.second};
	return ccw({0, 0}, t, tt) >= 0;
}

ll f(ll t){ //ternary search
	for(int i=0; i<n; i++){
		arr[i] = {v[i].x + v[i].dx*t, v[i].y + v[i].dy*t};
	}
	swap(arr[0], *min_element(arr.begin(), arr.end()));
	sort(arr.begin()+1, arr.end(), [](p a, p b){
		int cw = ccw(arr[0], a, b);
		if(cw) return cw > 0;
		return dist(arr[0], a) < dist(arr[0], b);
	});

	//get convx hull
	vector<p> hull;
	for(int i=0; i<n; i++){
		while(hull.size() >= 2 && ccw(hull[hull.size()-2], hull.back(), arr[i]) <= 0){
			hull.pop_back();
		}
		hull.push_back(arr[i]);
	}

	//rotating calipers
	ll ret = 0;
	int p = 0;

	for(int i=0; i<hull.size(); i++){
		while(p+1 < hull.size() && chk(hull[i], hull[i+1], hull[p], hull[p+1])){
			ret = max(ret, dist(hull[i], hull[p])); p++;
		}
		ret = max(ret, dist(hull[i], hull[p]));
	}

	return ret;
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> n >> t;
	v.resize(n), arr.resize(n);
	for(int i=0; i<n; i++) v[i].get();

	//ternary search
	ll s = 0, e = t;
	while(s+3 <= e){
		ll l = (s+s+e)/3, r = (s+e+e)/3;
		if(f(l) > f(r)) s = l;
		else e = r;
	}

	ll ans = 1e18;
	int idx = s;
	for(ll i=s; i<=e; i++){
		ll now = f(i);
		if(ans > now){
			ans = now;
			idx = i;
		}
	}
	cout << idx << "\n" << ans;
}

Compilation message

dist.cpp: In function 'll f(ll)':
dist.cpp:62:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<hull.size(); i++){
               ~^~~~~~~~~~~~
dist.cpp:63:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(p+1 < hull.size() && chk(hull[i], hull[i+1], hull[p], hull[p+1])){
         ~~~~^~~~~~~~~~~~~

Subtask #1
2.0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 256 KB Output is correct
9 Correct 3 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 256 KB Output is correct
9 Correct 3 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 11 ms 376 KB Output is correct
12 Correct 12 ms 504 KB Output is correct
13 Correct 9 ms 376 KB Output is correct
14 Correct 11 ms 376 KB Output is correct
15 Correct 12 ms 376 KB Output is correct
16 Correct 17 ms 376 KB Output is correct
17 Correct 11 ms 380 KB Output is correct
18 Correct 7 ms 376 KB Output is correct
19 Correct 9 ms 376 KB Output is correct
20 Correct 12 ms 376 KB Output is correct

Subtask #3
39.0 / 39.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 1784 KB Output is correct
2 Correct 85 ms 2424 KB Output is correct
3 Correct 85 ms 2428 KB Output is correct
4 Correct 80 ms 3460 KB Output is correct
5 Correct 101 ms 2552 KB Output is correct
6 Correct 112 ms 3376 KB Output is correct
7 Correct 72 ms 2168 KB Output is correct
8 Correct 54 ms 2168 KB Output is correct
9 Correct 79 ms 3484 KB Output is correct
10 Correct 95 ms 2424 KB Output is correct

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 256 KB Output is correct
9 Correct 3 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 11 ms 376 KB Output is correct
12 Correct 12 ms 504 KB Output is correct
13 Correct 9 ms 376 KB Output is correct
14 Correct 11 ms 376 KB Output is correct
15 Correct 12 ms 376 KB Output is correct
16 Correct 17 ms 376 KB Output is correct
17 Correct 11 ms 380 KB Output is correct
18 Correct 7 ms 376 KB Output is correct
19 Correct 9 ms 376 KB Output is correct
20 Correct 12 ms 376 KB Output is correct
21 Correct 95 ms 1784 KB Output is correct
22 Correct 85 ms 2424 KB Output is correct
23 Correct 85 ms 2428 KB Output is correct
24 Correct 80 ms 3460 KB Output is correct
25 Correct 101 ms 2552 KB Output is correct
26 Correct 112 ms 3376 KB Output is correct
27 Correct 72 ms 2168 KB Output is correct
28 Correct 54 ms 2168 KB Output is correct
29 Correct 79 ms 3484 KB Output is correct
30 Correct 95 ms 2424 KB Output is correct
31 Correct 396 ms 2504 KB Output is correct
32 Correct 387 ms 2336 KB Output is correct
33 Correct 388 ms 2352 KB Output is correct
34 Correct 370 ms 2552 KB Output is correct
35 Correct 419 ms 2488 KB Output is correct
36 Correct 388 ms 3476 KB Output is correct
37 Correct 350 ms 2424 KB Output is correct
38 Correct 222 ms 2424 KB Output is correct
39 Correct 295 ms 2508 KB Output is correct
40 Correct 401 ms 2552 KB Output is correct
41 Correct 413 ms 3472 KB Output is correct
42 Correct 395 ms 3420 KB Output is correct