Submission #625310

#	Time	Username	Problem	Language	Result	Execution time	Memory
625310		Lobo	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1446 ms	62496 KiB

jumps

#include "jumps.h"
#include<iostream>
#include<algorithm>
#include <vector>
#include <stack>
using namespace std;
#define fr first
#define sc second
#define mp make_pair
const int inf = 1e9+10;
const int maxn = 2e5+10;

int n, h[maxn], nx[maxn][23], nxl[maxn][23], nxr[maxn][23];
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,pos);
        return;
    }
    int mid = (l+r)>>1;
    att(2*no,l,mid,pos,val);
    att(2*no+1,mid+1,r,pos,val);
    tr[no] = max(tr[2*no],tr[2*no+1]);
}

pair<int,int> qrmx(int no, int l, int r, int L, int R) {
    if(l > R || r < L) return mp(-inf,0);
    if(l >= L && r <= R) {
        return tr[no];
    }
    int mid = (l+r)>>1;
    return max(qrmx(2*no,l,mid,L,R),qrmx(2*no+1,mid+1,r,L,R));
}
    
void init(int N, std::vector<int> H) {
    n = N;
    for(int i = 0; i < n; i++) {
        h[i] = H[i];
        att(1,0,n-1,i,h[i]);
    }

    stack<pair<int,int>> stk;
    for(int i = 0; i < n; i++) {
        while(stk.size() && stk.top().fr < h[i]) stk.pop();
        if(stk.size()) nxl[i][0] = stk.top().sc;
        else nxl[i][0] = n;
        stk.push(mp(h[i],i));
    }
    while(stk.size()) stk.pop();
    for(int i = n-1; i >= 0; i--) {
        while(stk.size() && stk.top().fr < h[i]) stk.pop();
        if(stk.size()) nxr[i][0] = stk.top().sc;
        else nxr[i][0] = n;
        stk.push(mp(h[i],i));
    }

    for(int i = 0; i < n; i++) {
        if(nxr[i][0] == n) nx[i][0] = nxl[i][0];
        else if(nxl[i][0] == n) nx[i][0] = nxr[i][0];
        else if(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] << endl; 
    }
    nx[n][0] = n;
    nxl[n][0] = n;
    nxr[n][0] = n;

    for(int j = 1; j <= 20; j++) {
        for(int i = 0; i <= n; i++) {
            nx[i][j] = nx[nx[i][j-1]][j-1];
            nxl[i][j] = nxl[nxl[i][j-1]][j-1];
            nxr[i][j] = nxr[nxr[i][j-1]][j-1];
            // cout << i << " " << j << " " << nx[i][j] << endl;
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    int ans = 0;
    int f = qrmx(1,0,n-1,C,D).sc;
    if(nxl[f][0] < n) A = max(A,nxl[f][0]+1);
    if(A > B) return -1;
    int v = qrmx(1,0,n-1,A,B).sc;
    // cout << f << " " << v << " " << nx[v][20] << endl;
    for(int j = 20; j >= 0; j--) {
        int nxv = nx[v][j];
        if(nxr[nxv][0] < C) {
            ans+= (1<<j);
            v = nxv;
        }
    }




    int v1 = v;
    int ans1 = ans;
    int v2 = nx[v][0];
    int ans2 = ans+1;
    // cout << v1 << " " << v2 << " " << ans1<< endl;
    ans = inf;
    for(int j = 20; j >= 0; j--) {
        int nxv = nxr[v1][j];
        // cout << j << "  " << v1 << " " << nxv << endl;
        if(nxv < C) {
            v1 = nxv;
            ans1+= (1<<j);
        }
    }
    // cout << v1 << " " << v2 << " " << ans1<< endl;
    if(C <= nxr[v1][0] && nxr[v1][0] <= D) ans = min(ans,ans1+1);
    for(int j = 20; j >= 0; j--) {
        int nxv = nxr[v2][j];
        if(nxv < C) {
            v2 = nxv;
            ans2+= (1<<j);
        }
    }
    // cout << v1 << " " << v2 << " " << ans2<< endl;
    if(C <= nxr[v2][0] && nxr[v2][0] <= D) ans = min(ans,ans2+1);

    if(ans == inf) return -1;
    return ans;
}

• 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