Submission #1164328

#	Time	Username	Problem	Language	Result	Execution time	Memory
1164328		Zero_OP	Worst Reporter 3 (JOI18_worst_reporter3)	C++20	100 / 100	556 ms	11396 KiB

worst_reporter3

#include <bits/stdc++.h>

using namespace std;

#define FOR(i, l, r) for(int i = (l); i < (r); ++i)
#define ROF(i, r, l) for(int i = (r) - 1; i >= (l); --i)

#define mp make_pair
#define mt make_tuple
#define ff first
#define ss second

#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define pb push_back
#define eb emplace_back
#define sz(v) (int)v.size()
#define sum_of(v) accumulate(all(v), 0ll)

#define dbg(x) "[" #x " = " << (x) << "]"

template<typename T>
      bool minimize(T& a, const T& b){
            if(a > b) return a = b, true;
            return false;
      }

template<typename T>
      bool maximize(T& a, const T& b){
            if(a < b) return a = b, true;
            return false;
      }

using ll = long long;
using db = double;
using ld = long double;
using ull = unsigned long long;

using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;

using vi = vector<int>;
using vb = vector<bool>;
using vc = vector<char>;
using vl = vector<ll>;
using vd = vector<db>;

using vpi = vector<pi>;
using vpl = vector<pl>;

void setIO(){
      ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef LOCAL
      freopen("task.inp", "r", stdin);
      freopen("task.out", "w", stdout);
#endif // LOCAL
}

const int inf = 1e9 + 10;

int ceil_div(int a, int b){
      return (a + b - 1) / b;
}

int main(){
      setIO();

      int N, Q;
      cin >> N >> Q;

      vi d(N+1);
      FOR(i, 1, N+1) cin >> d[i];

      vl step(N+1);
      step[1] = d[1];
      FOR(i, 2, N+1){
            if(step[i-1] == inf){
                  step[i] = inf;
                  continue;
            }

            step[i] = min(1LL * inf, step[i-1] * ceil_div(d[i], step[i-1]));
      }

      vi value = {step[1]};
      vector<vi> position = {{-1}};
      FOR(i, 2, N+1){
            if(step[i] == inf) break;
            if(step[i] != step[i-1]) value.pb(step[i]), position.pb({});
            position.back().pb(-i);
      }

      FOR(i, 0, sz(position)){
            reverse(all(position[i]));
      }

      //Person i : when T = k * step[i] => position = k * step[i] - i for 1 <= i <= N

      //number of distinct values of step[] <= log2(1e9)

      while(Q--){
            int T, L, R;
            cin >> T >> L >> R;

            int ans = L <= T && T <= R;
            FOR(i, 0, sz(value)){
                  int t = T / value[i];
                  t *= value[i];

                  int l = lower_bound(all(position[i]), L - t) - position[i].begin();
                  int r = upper_bound(all(position[i]), R - t) - position[i].begin();
                  ans += r - l;
            }
            cout << ans << '\n';
      }

      return 0;
}

/*

First one :
- For T = kD[1] : X[1] = kD[1]-1

Second one :
k * D[1] - 1 - (-2) >= D[2] + 1
<=> k >= ceil(D[2] / D[1])
<=> k = ceil(D[2] / D[1]) (for the first time)
<=> X[2] = ceil(D[2] / D[1]) * D[1] - 2

the second time person 2nd jumps
k' * D[1] - 1 - (ceil(D[2] / D[1]) * D[1] - 2) >= D[2] + 1
k' * D[1] >= (ceil(D[2] / D[1]) * D[1] + D[2])

=> k' >= 2* ceil(D[2] / D[1])

... (same for the k-th times)

generally : t = k * ceil(D[2] / D[1]) * D[1], position = k * ceil(D[2] / D[1]) * D[1] - 2

step[2] = ceil(D[2] / D[1]) * D[1]

Third one :
- For T = k * step[2] : second person : k * step[2] - 2

k * step[2] - 2 - (-3) >= D[3] + 1
<=> k * step[2] >= D[3]
<=> k >= ceil(D[3] / step[2])
first jump : k = ceil(D[3] / step[2]) * step[2]

*/

Compilation message (stderr)

worst_reporter3.cpp: In function 'int main()':
worst_reporter3.cpp:86:26: warning: narrowing conversion of 'step.std::vector<long long int>::operator[](1)' from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' [-Wnarrowing]
   86 |       vi value = {step[1]};
      |                          ^
worst_reporter3.cpp:86:26: warning: narrowing conversion of 'step.std::vector<long long int>::operator[](1)' from '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} to 'int' [-Wnarrowing]

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 81 / 81