Submission #943331

#	Time	Username	Problem	Language	Result	Execution time	Memory
943331		shoryu386	Road Construction (JOI21_road_construction)	C++17	100 / 100	6557 ms	41436 KiB

road_construction

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

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

#define int long long

template <typename T>
using pbds_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define N 250007
int fw[N];
void update(int x, int v){
	x++;
	for (; x < N; x+= x&(-x)) fw[x] += v;
}
int sum(int x) {
    x++;
    int res = 0;
    for(; x; x-=x&(-x)) res += fw[x];
    return res;
}
inline int range_sum(int x, int y) { //inclusive
    return sum(y)-sum(x-1);
}


main(){
	int n, k; cin >> n >> k;
	
	pair<int, int> arr[n];
	for (int x = 0; x < n; x++){
		cin >> arr[x].first >> arr[x].second;
	}
	
	//consider manhattan distance trick?
	for (int x = 0; x < n; x++){
		arr[x] = {arr[x].first + arr[x].second, arr[x].first - arr[x].second};
	}
	sort(arr, arr+n); //sorted by x-coord
	
	//now chebyshev distance, dist = max of difference
	
	//I want to bsearch, but bsearch only gives location of boundary; I need sum of boundary
	
	set<int> pts;
	for (int x = 0; x < n; x++){
		pts.insert(arr[x].second);
	}
	
	unordered_map<int, int> disc;
	vector<int> discPts;
	
	int ptr = 0;
	for (auto pt : pts){
		disc[pt] = ptr; ptr++;
		
		discPts.push_back(pt);
	}
	
	int l = 0, r = 4'000'000'000LL, ans = 4'000'000'000LL;
	while (l <= r){
		int m = (l+r)/2;
		int cnt = 0;
		
		memset(fw, 0, sizeof(fw));
		deque<pair<int, int>> pq;
		for (int x = 0; x < n; x++){
			while (!pq.empty() && pq.front().first <= arr[x].first){
				update(disc[arr[ pq.front().second ].second], -1);
				pq.pop_front();
			}
			
			//we want sum <= arr[x].second-m-1
			//we want sum <= arr[x].second+m
			
			int high = 0;
			auto upper = lower_bound(discPts.begin(), discPts.end(), arr[x].second+m+1);
			if (upper != discPts.begin()){
				high = disc[ *prev(upper) ];
			}
			
			int low = 0;
			auto lower = lower_bound(discPts.begin(), discPts.end(), arr[x].second-m);
			if (lower != discPts.begin()){
				low = disc[ *prev(lower) ];
			}
			
			cnt += sum(high) - sum(low);
			
			update(disc[arr[x].second], 1);
			pq.push_back({arr[x].first+m+1, x});
		}
		
		if (cnt < k){
			l = m+1;
		}
		else{
			ans = m;
			r = m-1;
		}
	}
	
	
	vector<int> clown;
	
	int ptrr = 0;
	multiset<pair<int, int>> ypts;
	for (int x = 0; x < n; x++){
		
		while (ptrr != n && arr[ptrr].first - arr[x].first <= ans){
			ypts.insert({arr[ptrr].second, arr[ptrr].first});
			ptrr++;
		}
		
		ypts.erase({arr[x].second, arr[x].first});
		for (auto y = ypts.lower_bound({arr[x].second - ans, LLONG_MIN}); y != ypts.lower_bound({arr[x].second + ans+1, LLONG_MIN}); y++){
			clown.push_back(max( y->second - arr[x].first, abs(arr[x].second - y->first) ) );
		}
	}
	
	sort(clown.begin(), clown.end());
	for (int x = 0; x < k; x++){
		if (x < clown.size()) cout << clown[x] << '\n';
		else cout << ans << '\n';
	}
}

Compilation message (stderr)

road_construction.cpp:30:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   30 | main(){
      | ^~~~
road_construction.cpp: In function 'int main()':
road_construction.cpp:126:9: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  126 |   if (x < clown.size()) cout << clown[x] << '\n';
      |       ~~^~~~~~~~~~~~~~

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