Submission #951469

#	Time	Username	Problem	Language	Result	Execution time	Memory
951469		hengliao	Rainforest Jumps (APIO21_jumps)	C++17	33 / 100	4046 ms	24452 KiB

jumps

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

#define F first
#define S second
#define pb push_back
#define vll vector<ll>
#define pll pair<ll, ll>
typedef long long ll;

const ll mxN=2e5+5;
const ll inf=1e18;

ll n;
vll h;
vll adj[mxN];
ll r[mxN];
ll l[mxN];
vll dis;

void init(int tn, vector<int> th){
    n=tn;
    h.resize(n);
    for(ll i=0;i<n;i++){
        h[i]=th[i];
    }
    vector<ll> stk;
    for(ll i=0;i<n;i++){
        if(!stk.empty()){
            ll lef=0, rig=stk.size()-1;
            ll tep=inf;
            while(lef<=rig){
                ll mid=(lef+rig)/2;
                if(stk[mid]>h[i]){
                    tep=min(tep, stk[mid]);
                    lef=mid+1;
                }
                else{
                    rig=mid-1;
                }
            }
            l[h[i]]=tep;
        }
        else{
            l[h[i]]=inf;
        }
        while(!stk.empty() && stk.back()<h[i]){
            stk.pop_back();
        }
        stk.pb(h[i]);
    }
    stk.clear();
    for(ll i=n-1;i>=0;i--){
        if(!stk.empty()){
            ll lef=0, rig=stk.size()-1;
            ll tep=inf;
            while(lef<=rig){
                ll mid=(lef+rig)/2;
                if(stk[mid]>h[i]){
                    tep=min(tep, stk[mid]);
                    lef=mid+1;
                }
                else{
                    rig=mid-1;
                }
            }
            r[h[i]]=tep;
        }
        else{
            r[h[i]]=inf;
        }
        while(!stk.empty() && stk.back()<h[i]){
            stk.pop_back();
        }
        stk.pb(h[i]);
    }
    for(ll i=1;i<=n;i++){
        if(l[i]!=inf){
            adj[i].pb(l[i]);
        }
        if(r[i]!=inf){
            adj[i].pb(r[i]);
        }
    }
    //cout<<"initializing\n";
    //for(ll i=1;i<=n;i++){
        //cout<<i<<' '<<l[i]<<' '<<r[i]<<'\n';
    //}
}

int minimum_jumps(int a, int b, int c, int d){
    dis=vll(n+1, inf);
    queue<pll> q;
    for(ll i=a;i<=b;i++){
        q.push({h[i], 0});
    }
    while(!q.empty()){
        pll cur=q.front();
        q.pop();
        if(dis[cur.F]!=inf){
            continue;
        }
        dis[cur.F]=cur.S;
        for(auto it:adj[cur.F]){
            q.push({it, cur.S+1});
        }
    }
    ll re=inf;
    for(ll i=c;i<=d;i++){
        re=min(re, dis[h[i]]);
        //cout<<h[i]<<' '<<dis[h[i]]<<'\n';
    }
    if(re==inf) return -1;
    else return (int) re;
}

/*int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n, q;
    cin>>n>>q;
    int h[n];
    for(ll i=0;i<n;i++){
        cin>>h[i];
    }
    init(n, h);
    for(ll i=0;i<q;i++){
        int a, b, c, d;
        cin>>a>>b>>c>>d;
        cout<<minimum_jumps(a, b, c, d)<<'\n';
    }
    return 0;
}*/

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