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  1.                               /*Bismillahir Rahmanir Raheem*/
  2. #include <bits/stdc++.h>
  3.  
  4. using namespace std;
  5.  
  6. #define kuka ios::sync_with_stdio(false);cin.tie(0), cout.tie(0);
  7. #define pb push_back
  8. #define sz(x) x.size()
  9. #define all(x) x.begin(), x.end()
  10. #define FOR(n) for(int i = 0; i < n; i++)
  11. #define ff(x, y) for( int y = 0; y < x; y++)
  12. #define fff(x, y) for( int y = x; y <= 0; y--)
  13. #define F first
  14. #define S second
  15. //#define int long long  
  16.  
  17. typedef long long ll;
  18. typedef unsigned long long ull;
  19. typedef long double ld;
  20.  
  21. mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
  22.  
  23. const ll INF = LLONG_MAX;
  24. const int inf = INT_MAX;
  25. const int N = 1e5 + 5;
  26. const int MOD = 1e9 + 7;	 
  27.  
  28. int n, L;
  29. ld d[N], v[N];
  30. ld pref_t[N], pref_s[N];
  31.  
  32. ld get() {
  33.     ld ans = 1e15;
  34.  
  35.     for (int i = 1; i <= n; i++) {
  36.         pref_t[i] = pref_t[i - 1] + ((ld)d[i] / (ld)v[i]);
  37.         pref_s[i] = pref_s[i - 1] + d[i];
  38.     }
  39.  
  40.     for (int i = 1; i <= n; i++) {
  41.         int l = i - 1, r = n + 1;
  42.  
  43.         while (r - l > 1) {
  44.             int mid = (l + r) / 2;
  45.             if (pref_s[mid] - pref_s[l] < L) {
  46.                 l = mid;
  47.             } else {
  48.                 r = mid;
  49.             }
  50.         }
  51.  
  52.         ld sum = pref_t[i - 1] + pref_t[n] - pref_t[l];
  53.         if (l < n) {
  54.             ld last = L - (pref_s[l] - pref_s[i - 1]);
  55.             if (l + 1 <= n) {
  56.                 sum += last / v[l + 1];
  57.             }
  58.         }
  59.         ans = min(ans, sum);
  60.     }
  61.  
  62.     return ans;
  63. }
  64.  
  65. void oyan() {
  66.     cin >> n >> L;
  67.     for (int i = 1; i <= n; i++) {
  68.         cin >> d[i];
  69.     }
  70.     for (int i = 1; i <= n; i++) {
  71.         cin >> v[i];
  72.     }
  73.  
  74.     ld ans1 = get();
  75.  
  76.     reverse(d + 1, d + n + 1);
  77.     reverse(v + 1, v + n + 1);
  78.  
  79.     ld ans2 = get();
  80.  
  81.     cout << fixed << setprecision(9) << min(ans1, ans2) << "\n";
  82. }
  83.  
  84.  
  85. main(){
  86.     kuka;
  87. 	//freopen("test.txt", "r", stdin);
  88. 	//freopen("distance.in", "r", stdin);
  89.     //freopen("distance.out", "w", stdout);
  90.     int oylan = 1;
  91.     //cin>>oylan;
  92.     while(oylan--){
  93.         oyan();
  94.     }
  95. }
  96. /*
  97. NOTES
  98. a/b module == (a*b^(module - 2)) % (module);
  99.  
  100. ll binpow(int n, int k) {
  101. 	if (k == 0) {
  102. 		return 1;
  103. 	}if (k % 2 == 0) {
  104. 		ll val = binpow(n, (k / 2));
  105. 		return val * val % MOD;
  106. 	}
  107. 	return (binpow(n, k - 1) * n) % MOD;
  108. }
  109. */
Success #stdin #stdout 0.01s 5288KB
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stdin
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Standard input is empty
stdout
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1000000000000000.000000000
https://ideone.com/ThlvBQ
language:
C++14 (gcc 8.3)
created:
5 hours ago
visibility:
public

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