Submission #998897

#	Time	Username	Problem	Language	Result	Execution time	Memory
998897		hippo123	Balloons (CEOI11_bal)	C++17	10 / 100	626 ms	21668 KiB

bal

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

#define pr pair<double, int>
#define ll long long
#define pb push_back
#define f first
#define s second
vector<double> x, r;
set<pr> xr;

bool check(double mid, set<pr>::iterator it1, set<pr>::iterator it2, int be){
	
	bool judge=false;
	
	for (auto it=it1; it!=it2; it++){
		int pos=it->s;
		double rr=(mid+r[pos])*(mid+r[pos]);
		
		double dist1=(mid-r[pos])*(mid-r[pos])+(x[be]-x[pos])*(x[be]-x[pos]);

		if(rr>=dist1){
			judge=true; break;
		}
	}
	
	return judge;
		
}
	

int main(){
	int n; cin>>n;
	x.resize(n); r.resize(n);
	for (int i=0; i<n; i++) {
		cin>>x[i]>>r[i];
		pr node={x[i]+r[i], i};
		xr.insert(node); // r value changes and this need to be update
	}

	vector<double> ans(n);
	for (int i=0; i<n; i++){
		if(i==0) {
			ans[i]=r[i]; 
			continue;
		}
		//
		pr node={x[i]-r[i], i};
		set<pr>::iterator it1=xr.lower_bound(node); // pos can only be less than or equal to i;
		node={x[i]+r[i], i};
		set<pr>::iterator it2=xr.find(node);
		

		
		if(it1==it2) {ans[i]=r[i]; continue;}
		
		double lft=0; double rht=r[i]; 
		while(rht-lft>0.00001){
			double mid=lft+(rht-lft)/2;

			if(check(mid, it1, it2, i)) {
				rht=mid;
			}
			else lft=mid;			
			
		}
		ans[i]=lft;
		
		xr.erase(node);
		node={x[i]+lft, i};
		xr.insert(node);
	}
	cout << fixed <<setprecision(3);
	for (int i=0; i<n; i++) cout<<ans[i]<<endl;
}

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10