Submission #975149

#	Time	Username	Problem	Language	Result	Execution time	Memory
975149		yoav_s	Rainforest Jumps (APIO21_jumps)	C++17	77 / 100	4038 ms	61488 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

typedef int 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;
vv largestLifting;
v rightHeight;
ll logN;
v nextLargest;
vv nextLifting;

ll query(ll l, ll r, v &st, bool maxi = true)
{
    ll n = st.size() / 2;
    l += n;
    r += n;
    ll res = maxi? -INF : INF;
    while (l <= r)
    {
        if (l % 2 == 1)
        {
            if (maxi)
                res = max(res, st[l]);
            else
                res = min(res, st[l]);
            l++;
        }
        if (r % 2 == 0)
        {
            if (maxi)
                res = max(res,st[r]);
            else
                res = min(res, st[l]);
            r--;
        }
        l /= 2;
        r /= 2;
    }
    return res;
}

ll largestSmaller(ll l, ll r, ll threshold, v &st)
{
    ll n = st.size() / 2;
    l += n;
    r += n;
    v segs, segsRev;
    while (l <= r)
    {
        if (l % 2 == 1)
        {
            segs.pb(l); l++;
        }
        if (r % 2 == 0)
        {
            segsRev.pb(r); r--;
        }
        l /= 2; r /= 2;
    }
    reverse(all(segs));
    for (ll x : segs) segsRev.pb(x);
    v relevantSegs;
    ll lastSeg = -1;
    for (ll x : segsRev)
    {
        if (st[x] >= threshold)
        {
            lastSeg = x;
            break;
        }
        relevantSegs.pb(x);
    }
    ll lastSegMaxi = -INF;
    if (lastSeg != -1)
    {
        ll cur = lastSeg;
        while (cur < n)
        {
            if (st[2 * cur + 1] < threshold)
            {
                lastSegMaxi = max(lastSegMaxi, st[2 * cur + 1]);
                cur *= 2;
            }
            else cur = 2 * cur + 1;
        }
    }
    ll best = -INF;
    for (ll x : relevantSegs) best = max(best, st[x]);
    if (best > lastSegMaxi)
    {
        for (ll x : relevantSegs)
        {
            if (st[x] == best)
            {
                ll cur = x;
                while (cur < n)
                {
                    if (st[2 * cur] == best) cur *= 2;
                    else cur = 2 * cur + 1;
                }
                return cur - n;
            }
        }
    }
    if (lastSegMaxi == -INF) return -1;
    ll cur = lastSeg;
    while (cur < n)
    {
        if (st[2 * cur + 1] >= lastSegMaxi) cur = 2 * cur + 1;
        else cur *= 2;
    }
    return cur - n;
}

void init(int Nn, std::vector<int> Hh) {
    vp hSorted;
    for (ll i =0 ; i < Nn; i++) hSorted.eb(Hh[i], i);
    sort(all(hSorted));
    H = v(Nn, -1);
    for (ll i = 0; i < hSorted.size(); i++) H[hSorted[i].s] = i;
    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]);
    nextLargest = v(N, -1);
    for (ll i = 0; i < N; i++)
    {
        if (nextHigher[i] != N) nextLargest[i] = nextHigher[i];
        if (prevHigher[i] != -1 && (nextLargest[i] == -1 || H[nextLargest[i]] < H[prevHigher[i]])) nextLargest[i] = prevHigher[i];
    }
    logN = log2(N);
    largestLifting = vv(N, v(logN + 1, -1));
    for (ll i = 0; i < N; i++) largestLifting[i][0] = nextLargest[i];
    for (ll iter = 1; iter <= logN; iter++)
    {
        for (ll i= 0; i < N; i++)
        {
            if (largestLifting[i][iter - 1] == -1) largestLifting[i][iter] = -1;
            else largestLifting[i][iter] = largestLifting[largestLifting[i][iter - 1]][iter - 1];
        }
    }
    vv nextHigherRev(N + 1);
    for (ll i =0; i <N; i++) nextHigherRev[nextHigher[i]].pb(i);
    rightHeight = v(N + 1, 0);
    stack<p> dfs;
    dfs.emplace(N, 0);
    while (!dfs.empty())
    {
        auto top = dfs.top();
        dfs.pop();
        rightHeight[top.f] = top.s;
        for (ll x : nextHigherRev[top.f]) dfs.emplace(x, top.s + 1);
    }
    nextLifting = vv(N + 1, v(logN + 1, N));
    for (ll i = 0; i < N; i++) nextLifting[i][0] = nextHigher[i];
    for (ll i = 1; i <= logN; i++)
    {
        for (ll j = 0; j < N; j++)
        {
            nextLifting[j][i] = nextLifting[nextLifting[j][i - 1]][i - 1];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    ll mini = INF;
    for (ll j = C; j <= D; j++)
    {
        ll i = largestSmaller(A, B, H[j], st);
        if (i == -1 || query(i, j - 1, st, true) > H[j]) continue;
        ll steps = 0;
        ll cur = i;
        for (ll k = logN; k >= 0; k--)
        {
            if (largestLifting[cur][k] != -1 && H[largestLifting[cur][k]] <= H[j])
            {
                cur = largestLifting[cur][k];
                steps += (1 << k);
            }
        }
        steps += abs(rightHeight[cur] - rightHeight[j]);
        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:253:1: warning: "/*" within comment [-Wcomment]
  253 | /**/
      |  
jumps.cpp:27:16: warning: overflow in conversion from 'double' to 'll' {aka 'int'} changes value from '1.0e+18' to '2147483647' [-Woverflow]
   27 | const ll INF = 1e18;
      |                ^~~~
jumps.cpp: In function 'void init(int, std::vector<int>)':
jumps.cpp:152:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'int'} and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |     for (ll i = 0; i < hSorted.size(); i++) H[hSorted[i].s] = i;
      |                    ~~^~~~~~~~~~~~~~~~

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