Submission #549784

#	Time	Username	Problem	Language	Result	Execution time	Memory
549784		fcmalkcin	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	269 ms	40156 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 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,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;
        for (int t=1;t<20;t++) nxtmx[id][t]=nxtmx[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;

    for (int t=19;t>=0;t--)
    {
        ll h=nxtmx[nw][t];
        if (nxtr[h][0]<=d)
        {
            ans+=(1ll<<t);
            nw=h;
        }
    }

    for (int t=19;t>=0;t--)
    {
        if (nxtr[nw][t]<=d)
        {
        //    cout <<nw<<" "<<t<<" wtf"<<" "<<nxtr[nw][t]<<endl;
            nw=nxtr[nw][t];
            ans+=(1ll<<t);
        }
    }
  //  cout <<nw<<" "<<nxtr[nw][0]<<" "<<nxtmx[nw][0]<<" "<<nxtr[nw][0]<<endl;
    if (nw>=c)
    {
        return ans;
    }
    else
    {
        return -1;
    }
}
/*int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen("t.inp","r"))
    {
        freopen("test.inp","r",stdin);
        freopen("test.out","w",stdout);
    }
    ll a[10]={3, 2, 1, 6, 4, 5, 7};
    init(7,a);
    cout <<minimum_jumps(4, 4, 6, 6);

}*/

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