Submission #549814

#	Time	Username	Problem	Language	Result	Execution time	Memory
549814		fcmalkcin	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1204 ms	66132 KiB

jumps

#include<bits/stdc++.h>
using namespace std;

#define ll int
#define pll pair<ll,ll>
#define ff first
#define ss second
#define endl "\n"
#define pb push_back
#define F(i,a,b) for(ll i=a;i<=b;i++)

const ll maxn=3e5+10 ;
const ll base=1e9;
const ll mod= 1e9+7 ;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

/// have medal in APIO
/// goal 2/8

ll nxtr[maxn][20];
ll nxtl[maxn][20];
ll nxtmx[maxn][20];
ll mxnxtmx[maxn][20];

ll b[maxn];
ll pos[maxn];

void init(ll n,vector<ll> a)
{
    stack<ll> st;
    for (int t=0; t<20; t++)
        nxtr[n+1][t]=n+1;
    for (int i=n; i>=1; i--)
    {
        pos[a[i-1]]=i;
        while (st.size()&&a[st.top()-1]<a[i-1])
            st.pop();
        if (st.size())
            nxtr[i][0]=st.top();
        else
            nxtr[i][0]=n+1;
        for (int t=1; t<20; t++)
            nxtr[i][t]=nxtr[nxtr[i][t-1]][t-1];
        st.push(i);
    }
    while (st.size())
        st.pop();
    for (int i=1; i<=n; i++)
    {
        while (st.size()&&a[st.top()-1]<a[i-1])
            st.pop();
        if (st.size())
            nxtl[i][0]=st.top();
        else
            nxtl[i][0]=0;
        for (int t=1; t<20; t++)
            nxtl[i][t]=nxtl[nxtl[i][t-1]][t-1];
        st.push(i);
    }
    for (int i=n; i>=1; i--)
    {
        pll nw=make_pair(0,pos[i]);
        ll id=pos[i];
        if (nxtl[id][0]!=0)
        {
            nw=max(nw,make_pair(a[nxtl[id][0]-1],nxtl[id][0]));
        }
        if (nxtr[id][0]!=n+1)
        {
            nw=max(nw,make_pair(a[nxtr[id][0]-1],nxtr[id][0]));
        }
        nxtmx[id][0]=nw.ss;
        mxnxtmx[id][0]=nxtr[nw.ss][0];
        for (int t=1; t<20; t++)
            nxtmx[id][t]=nxtmx[nxtmx[id][t-1]][t-1],mxnxtmx[id][t]=max(mxnxtmx[id][t-1],mxnxtmx[nxtmx[id][t-1]][t-1]);
    }
}
ll minimum_jumps(ll a,ll b,ll c,ll d)
{
    a++;
    b++;
    c++;
    d++;
    ll nw=b;
    for (int t=19; t>=0; t--)
    {
        if (nxtr[nxtl[nw][t]][0]<=d&&nxtl[nw][t]>=a)
        {
            nw=nxtl[nw][t];
        }
    }

    if (nxtr[nw][0]>d)
        return -1;
    ll ans=0;
    if (nxtr[nw][0]>=c)
    {
        return 1;
    }
    for (int t=19; t>=0; t--)
    {
        ll h=nxtmx[nw][t];
        if (nxtr[h][0]<c)
        {
            ans+=(1ll<<t);
            nw=h;
        }
    }
    if (nxtmx[nw][0]<=d&&nxtmx[nw][0]>=c)
    {
        return ans+1;
    }
    if (nxtr[nxtmx[nw][0]][0]<=d)
    {
        nw=nxtmx[nw][0];
        ans++;
    }
    if (nw>=c)
    {
        return ans;
    }
    // cout <<nw<<" "<<nxtr[nw][0]<<" "<<nxtmx[nw][0]<<" "<<nxtr[nxtmx[nw][0]]<<" "<<ans<<endl;
    for (int t=19; t>=0; t--)
    {
        if (nxtr[nw][t]<c)
        {
            //    cout <<nw<<" "<<t<<" wtf"<<" "<<nxtr[nw][t]<<endl;
            nw=nxtr[nw][t];
            ans+=(1ll<<t);
        }
    }
    ans++;
    nw=nxtr[nw][0];
    //  cout <<nw<<" "<<nxtr[nw][0]<<" "<<nxtmx[nw][0]<<" "<<nxtr[nw][0]<<endl;
    if (nw<=d)
    {
        return ans;
    }
    else
    {
        return -1;
    }
}

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