Submission #1067376

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067376		TimDee	Seesaw (JOI22_seesaw)	C++17	100 / 100	59 ms	12268 KiB

seesaw

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

#define int long long
#define forn(i,n) for(int i=0; i<n; ++i)
#define vii(a,n) vector<int> a(n); forn(i,n) cin>>a[i];
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(),x.end()

const double eps = 1e-9;
void solve() {
	
	int n; cin>>n;
	vii(a,n);
	vector<pair<double,int>> v;
	int s=0; forn(i,n) s+=a[i];
	double c = 1.0*s/n;

	int l=0, r=n-1;
	while (l<=r) {
		int m=r-l+1;
		v.pb({1.0*s/m,m-1});
		if (l==r) break;
		double z = 1.0*(s-a[r])/(m-1);
		if (z>=c) {
			s-=a[r]; --r;
		} else {
			s-=a[l]; ++l;
		}
	}
	s=0, l=0, r=n-1; forn(i,n) s+=a[i];
	while (l<=r) {
		int m=r-l+1;
		v.pb({1.0*s/m,m-1});
		if (l==r) break;
		double z = 1.0*(s-a[l])/(m-1);
		if (z<=c) {
			s-=a[l]; ++l;
		} else {
			s-=a[r]; --r;
		}
	}

	sort(all(v));	
	//for(auto&x:v) cout<<'('<<x.f<<','<<x.s<<") ";
	vector<int> cnt(n);
	int tot=0;
	r=0;
	double ans=a[n-1]-a[0];
	forn(i,v.size()) {
		while (r<v.size() && tot<n) {
			tot+=!cnt[v[r].s];
			++cnt[v[r].s];
			++r;
		}
		if (tot==n) ans=min(ans,v[r-1].f - v[i].f);
		--cnt[v[i].s];
		tot-=!cnt[v[i].s];
	}
	cout<<fixed<<setprecision(10)<<ans<<'\n';

}

int32_t main() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	solve();
}

Compilation message (stderr)

seesaw.cpp: In function 'void solve()':
seesaw.cpp:5:33: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<double, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define forn(i,n) for(int i=0; i<n; ++i)
......
   52 |  forn(i,v.size()) {
      |       ~~~~~~~~~~                 
seesaw.cpp:52:2: note: in expansion of macro 'forn'
   52 |  forn(i,v.size()) {
      |  ^~~~
seesaw.cpp:53:11: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<double, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |   while (r<v.size() && tot<n) {
      |          ~^~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 33 / 33
• Subtask 3: 33 / 33
• Subtask 4: 33 / 33