59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
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#include<bits/stdc++.h>
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using namespace std;
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#define ll long long
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#define ul unsigned long long
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#define pb push_back
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#define ss second
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#define ff first
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#define fr(m) for(int i=0; i<m; ++i)
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#define fro(m) for(int i=1; i<m; ++i)
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#define frj(m) for(int j=0; j<m; ++j)
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#define frr(n) for(int i=n; i>=0; --i)
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#define nl '\n'
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#define yes cout<<"YES"<<nl
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#define no cout<<"NO"<<nl
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#define all(x) x.begin(), x.end()
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#define dbg(x) cerr << #x <<" "<< x << endl;
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#define fast_io (ios_base:: sync_with_stdio(false),cin.tie(NULL));
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ll fact(ll n){ if(n==0) return 1; ll res = 1; for (ll i = 2; i <= n; i++) res = res * i; return res;}
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ll nPr(ll n, ll r) { return fact(n) / fact(n - r); }
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ll nCr(ll n, ll r) { return fact(n) / (fact(r) * fact(n - r)); }
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ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
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ll lcm(ll a, ll b) { return (a * b) / gcd(a, b);}
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ll mypow(ll a, ll b){ ll ans = 1; while(b){ if (b&1) ans = (ans*a) ; b /= 2; a = (a*a); } return ans; }
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bool isPrime(ll n) { if(n <= 1) return false; for(ll i = 2; i <= sqrt(n); i++) if(n % i == 0) return false; return true;}
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#define PI 3.141592653589793238;
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#define INF LONG_LONG_MAX;
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#define MOD 1e9+7;
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//////////////////////////////////Code Start/////////////////////////////////////
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void solve()
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{
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int n,l;
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cin>>n>>l;
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vector<int>lamps(n);
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fr(n)
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cin>>lamps[i];
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int mx=0;
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sort(all(lamps));
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fro(n)
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{
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int x=lamps[i]-lamps[i-1];
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mx=max(x,mx);
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}
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cout<<showpoint<<fixed<<setprecision(10);
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double dis=max(lamps[0]-0, l - lamps[n - 1]);
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cout<<max(dis,(double)mx/2)<<nl;
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}
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int main()
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{
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fast_io;
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int TC = 1;
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//cin >> TC;
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while (TC--) solve();
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}
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