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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. typedef long long ll;
  4.  
  5. #define           f     first
  6. #define           s     second
  7. #define           pb    push_back
  8. #define           ep    emplace
  9. #define           eb    emplace_back
  10. #define           lb    lower_bound
  11. #define           ub    upper_bound
  12. #define       all(x)    x.begin(), x.end()
  13. #define      rall(x)    x.rbegin(), x.rend()
  14. #define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
  15. #define     mem(f,x)    memset(f , x , sizeof(f))
  16. #define        sz(x)    (ll)(x).size()
  17. #define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
  18. #define          mxx    *max_element
  19. #define          mnn    *min_element
  20. #define    cntbit(x)    __builtin_popcountll(x)
  21. #define       len(x)    (int)(x.length())
  22.  
  23. const int maxn = 2e6 + 100;
  24. int n, num[maxn], q[maxn], ok[maxn]; 
  25. ll m, sum = 0, f[maxn];
  26.  
  27. struct fake_set{
  28.     priority_queue <ll, vector <ll>, greater <ll>> good, bad;
  29.     int sz = 0;
  30.     void add(ll x) {
  31.         sz++;
  32.         good.push(x);
  33.     }
  34.  
  35.     void er(ll x) {
  36.         sz--;
  37.         bad.push(x);
  38.     }
  39.  
  40.     ll get() {
  41.         while (1) {
  42.             ll t = good.top();
  43.             ll v = sz(bad) ? bad.top() : -1e16;
  44.  
  45.             if (t == v) {
  46.                 bad.pop();
  47.                 good.pop();
  48.             } else {
  49.                 return t;
  50.             }
  51.         }
  52.  
  53.         return 0;
  54.     }
  55. };
  56.  
  57. int main() {
  58.     ios_base::sync_with_stdio(0);
  59.     cin.tie(0);
  60.     cout.tie(0);
  61.  
  62.     cin >> n >> m;
  63.     mem(f, 0x3f);
  64.  
  65.     f[0] = 0;
  66.  
  67.     for(int i = 1; i <= n; ++i) {
  68.        cin >> num[i];
  69.     }
  70.  
  71.     fake_set pq;
  72.     int head = 0, tail = 0, pos = 0;
  73.     ll sum = 0;
  74.  
  75.     for (int i = 1; i <= n; ++i) {
  76.         sum += num[i];
  77.         while (sum > m)
  78.             sum -= num[++pos];
  79.  
  80.         while (head <= tail && q[head] <= pos) {
  81.             ++head;
  82.             if (ok[head]) {
  83.                 ok[head] = 0;
  84.                 pq.er(f[q[head - 1]] + num[q[head]]);
  85.             }
  86.         }
  87.  
  88.         while (head <= tail && num[q[tail]] <= num[i]) {
  89.             if (ok[tail]) {
  90.                 ok[tail] = 0;
  91.                 pq.er(f[q[tail - 1]] + num[q[tail]]);
  92.             }
  93.             --tail;
  94.         }
  95.  
  96.         q[++tail] = i;
  97.         ok[tail] = 0;
  98.  
  99.         if (tail > head) {
  100.             pq.add(f[q[tail - 1]] + num[q[tail]]);
  101.             ok[tail] = 1;
  102.         }
  103.  
  104.         f[i] = f[pos] + num[q[head]] - 1;
  105.         if (pq.sz)
  106.             f[i] = min(f[i], pq.get() - 1);
  107.     }
  108.  
  109.     cout << f[n] + n << '\n';
  110.  
  111.     return 0;
  112. }
  113.  
Success #stdin #stdout 0.01s 19872KB
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https://ideone.com/rjPIpz
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

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