Submission #1104554

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104554		penguinhacker	Road Construction (JOI21_road_construction)	C++17	100 / 100	1623 ms	13768 KiB

road_construction

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

#define ll long long
#define ar array

const int mxN=250000;
int n, k;
ar<ll, 2> a[mxN];
vector<ll> ans;

bool ok(ll x) {
	ans.clear();
	set<ar<ll, 2>> s;
	for (int i=0, j=0; ans.size()<k&&i<n; ++i) {
		for (; a[i][0]-a[j][0]>x; ++j)
			s.erase({a[j][1], a[j][0]});
		for (auto it=s.lower_bound({a[i][1]-x, (ll)-1e10}); ans.size()<k&&it!=s.end()&&(*it)[0]<=a[i][1]+x; ++it)
			ans.push_back(max(a[i][0]-(*it)[1], abs(a[i][1]-(*it)[0])));
		s.insert({a[i][1], a[i][0]});
	}
	return ans.size()<k;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> k;
	for (int i=0; i<n; ++i) {
		ll x, y;
		cin >> x >> y;
		a[i]={x+y, x-y};
	}
	sort(a, a+n);
	ll lb=0, rb=4e9;
	while(lb<rb) {
		ll mid=(lb+rb+1)/2; // look for max number so <k roads with that many
		if (ok(mid))
			lb=mid;
		else
			rb=mid-1;
	}
	ok(lb);
	sort(ans.begin(), ans.end());
	for (ll i : ans)
		cout << i << "\n";
	for (int i=0; i<k-ans.size(); ++i)
		cout << lb+1 << "\n";
	return 0;
}

Compilation message (stderr)

road_construction.cpp: In function 'bool ok(long long int)':
road_construction.cpp:15:31: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   15 |  for (int i=0, j=0; ans.size()<k&&i<n; ++i) {
      |                     ~~~~~~~~~~^~
road_construction.cpp:18:65: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   18 |   for (auto it=s.lower_bound({a[i][1]-x, (ll)-1e10}); ans.size()<k&&it!=s.end()&&(*it)[0]<=a[i][1]+x; ++it)
      |                                                       ~~~~~~~~~~^~
road_construction.cpp:22:19: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |  return ans.size()<k;
      |         ~~~~~~~~~~^~
road_construction.cpp: In function 'int main()':
road_construction.cpp:47:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |  for (int i=0; i<k-ans.size(); ++i)
      |                ~^~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 6 / 6
• Subtask 3: 7 / 7
• Subtask 4: 20 / 20
• Subtask 5: 27 / 27
• Subtask 6: 35 / 35