Submission #569786

#	Time	Username	Problem	Language	Result	Execution time	Memory
569786		Lobo	Rainforest Jumps (APIO21_jumps)	C++17	48 / 100	1747 ms	67148 KiB

jumps

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

const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 2e5+10;

int n, h[maxn], nx[maxn][25], nxl[maxn][25], nxr[maxn][25];

pair<int,int> tr[4*maxn];

void att(int no, int l, int r, int pos, int val) {
    if(l > pos || r < pos) return;
    if(l == r) {
        tr[no] = mp(val,l);
        return;
    }
    int f1 = 2*no;
    int f2 = 2*no+1;
    int mid = (l+r)/2;
    att(f1,l,mid,pos,val);
    att(f2,mid+1,r,pos,val);
    tr[no] = max(tr[f1],tr[f2]);
}

pair<int,int> qrrmx(int no, int l, int r, int L, int R) {
    if(l > R || r < L) return mp(0,0);
    if(l >= L && r <= R) return tr[no];
    int f1 = 2*no;
    int f2 = 2*no+1;
    int mid = (l+r)/2;
    return max(qrrmx(f1,l,mid,L,R),qrrmx(f2,mid+1,r,L,R));
}

void init(int N, vector<int> H) {
    n = N;

    for(int i = 1; i <= n; i++) {
        h[i] = H[i-1];
        att(1,1,n,i,h[i]);
    }
    //os proximos da esquerda e direita de cada um e 0 se não tiver
    stack<pair<int,int>> stl;
    for(int i = 1; i <= n; i++) {
        while(stl.size() && stl.top().fr < h[i]) {
            stl.pop();
        }

        if(stl.size()) nxl[i][0] = stl.top().sc;
        else nxl[i][0] = 0;

        stl.push(mp(h[i],i));
    }
    stack<pair<int,int>> str;
    for(int i = n; i >= 1; i--) {
        while(str.size() && str.top().fr < h[i]) {
            str.pop();
        }

        if(str.size()) nxr[i][0] = str.top().sc;
        else nxr[i][0] = 0;

        str.push(mp(h[i],i));
    }

    //sei qual o proximo normal de cada um
    for(int i = 1; i <= n; i++) {
        if(nxr[i][0] == 0 || h[nxl[i][0]] > h[nxr[i][0]]) nx[i][0] = nxl[i][0];
        else nx[i][0] = nxr[i][0];

        // cout << i << " " << nx[i][0] << " " << nxl[i][0] << " " << nxr[i][0] << endl;
    }

    for(int pt = 1; pt <= 20; pt++) {
        for(int i = 1; i <= n; i++) {
            nx[i][pt] = nx[nx[i][pt-1]][pt-1];
        }
    }
    for(int pt = 1; pt <= 20; pt++) {
        for(int i = 1; i <= n; i++) {
            nxl[i][pt] = nxl[nxl[i][pt-1]][pt-1];
        }
    }
    for(int pt = 1; pt <= 20; pt++) {
        for(int i = 1; i <= n; i++) {
            nxr[i][pt] = nxr[nxr[i][pt-1]][pt-1];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    A++;
    B++;
    C++;
    D++;
    //ir do a para o c

    //pego o maior cara entre a e b < c
    //na vez do h[c] qual era o maior do intervalo
    
    int s = 0;
    int l = A;
    int r = B;
    while(l <= r) {
        int mid = (l+r)/2;
        // cout << mid << " " << qrrmx(1,1,n,mid,B).fr << endl;
        if(qrrmx(1,1,n,mid,B).fr < h[C]) {
            s = mid;
            r = mid-1;
        }
        else {
            l = mid+1;
        }
    }
    if(s == 0) return -1;
    s = qrrmx(1,1,n,s,B).sc;
    int t = C;
    int ans = n+10;
    int ans1 = 0;
    for(int pt = 20; pt >= 0; pt--) {
        if(nx[s][pt] == 0 || h[nx[s][pt]] > h[t]) continue;
        ans1+= (1<<pt);
        s = nx[s][pt];
    }
    //vai so para a direita ate chegar no t
    for(int pt = 20; pt >= 0; pt--) {
        if(nxr[s][pt] == 0 || nxr[s][pt] > t) continue;
        ans1+= (1<<pt);
        s = nxr[s][pt];
    }
    if(s == t) ans = min(ans, ans1);
    if(ans <= n) return ans;
    else return -1;
}

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