Submission #975082

#	Time	Username	Problem	Language	Result	Execution time	Memory
975082		yoav_s	Rainforest Jumps (APIO21_jumps)	C++17	8 / 100	4054 ms	12524 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll, ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()

const ll INF = 1e18;
const ll mod = 1e9 + 7;

#include "jumps.h"

v H;
ll N;
v nextHigher;
v prevHigher;
v st;
ll n;

ll query(ll l, ll r)
{
    l += n;
    r += n;
    ll res = -INF;
    while (l <= r)
    {
        if (l % 2 == 1)
        {
            res = max(res, st[l]);
            l++;
        }
        if (r % 2 == 0)
        {
            res = max(res,st[r]);
            r--;
        }
        l /= 2;
        r /= 2;
    }
    return res;
}

void init(int Nn, std::vector<int> Hh) {
    H = v();
    for (auto x : Hh) H.pb(x);
    N = Nn;
    nextHigher = v(N, N);
    stack<p> mon;
    for (ll i = N - 1; i >= 0; i--)
    {
        while (!mon.empty() && mon.top().s <= H[i]) mon.pop();
        if (!mon.empty()) nextHigher[i] = mon.top().f;
        mon.emplace(i, H[i]);
    }
    mon = stack<p>();
    prevHigher = v(N, -1);
    for (ll i = 0; i < N; i++)
    {
        while (!mon.empty() && mon.top().s <= H[i]) mon.pop();
        if (!mon.empty()) prevHigher[i] = mon.top().f;
        mon.emplace(i, H[i]);
    }
    n = pow(2, ceil(log2(N)));
    st = v(2 * n, -INF);
    for (ll i = 0; i < N; i++) st[n + i] = H[i];
    for (ll i = n - 1;  i> 0; i--) st[i] = max(st[2 * i], st[2 * i + 1]);
}

int minimum_jumps(int A, int B, int C, int D) {
    ll mini = INF;
    for (ll i = A; i <= B; i++)
    {
        for (ll j = C; j <= D; j++)
        {
            if (query(i, j) == H[j])
            {
                ll steps = 0;
                ll cur = i;
                while (cur != j)
                {
                    ll next = -1;
                    if (prevHigher[cur] != -1 && H[prevHigher[cur]] <= H[j]) next = prevHigher[cur];
                    if (nextHigher[cur] != N && H[nextHigher[cur]] <= H[j] && (next == -1 || H[next] < H[nextHigher[cur]])) next = nextHigher[cur];
                    steps++;
                    cur = next;
                }
                mini = min(mini, steps);
            }
        }
    }
    if (mini == INF) mini = -1;
    return mini;
}
/*
int main() {
  int N, Q;
  assert(2 == scanf("%d %d", &N, &Q));
  std::vector<int> H(N);
  for (int i = 0; i < N; ++i) {
    assert(1 == scanf("%d", &H[i]));
  }
  init(N, H);

  for (int i = 0; i < Q; ++i) {
    int A, B, C, D;
    assert(4 == scanf("%d %d %d %d", &A, &B, &C, &D));
    printf("%d\n", minimum_jumps(A, B, C, D));
  }
  return 0;
}
/**/

Compilation message (stderr)

jumps.cpp:130:1: warning: "/*" within comment [-Wcomment]
  130 | /**/
      |

• Subtask 1: 0 / 4
• Subtask 2: 8 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 0 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19