Submission #416547

#	Time	Username	Problem	Language	Result	Execution time	Memory
416547		doowey	Rainforest Jumps (APIO21_jumps)	C++14	33 / 100	4059 ms	32052 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair

const int N = (int)2e5 + 10;
const int LOG = 18;

int n;
vector<int> H;
pii tab[LOG][N];
int LG[N];

pii get(int lf, int rf){
    int ag = LG[rf - lf + 1];
    return max(tab[ag][lf], tab[ag][rf - (1 << ag) + 1]);
}

int lef[N];
int rig[N];

void init(int _N, vector<int> _H) {
    n = _N;
    H = _H;
    for(int i = 0 ; i < n; i ++ ){
        tab[0][i] = mp(H[i], i);
    }
    vector<int> ids;
    for(int i = 0 ; i < n; i ++ ){
        while(!ids.empty() && H[i] > H[ids.back()]){
            ids.pop_back();
        }
        if(!ids.empty())
            lef[i] = ids.back();
        else
            lef[i] = -1;
        ids.push_back(i);
    }
    ids.clear();
    for(int i = n - 1; i >= 0 ; i -- ){
        while(!ids.empty() && H[i] > H[ids.back()]){
            ids.pop_back();
        }
        if(!ids.empty())
            rig[i] = ids.back();
        else
            rig[i] = -1;
        ids.push_back(i);
    }
    int pak = 0;
    for(int i = 1; i <= n; i ++ ){
        while((1 << (pak + 1)) <= i){
            pak ++ ;
        }
        LG[i] = pak;
    }
    for(int lg = 1; lg < LOG; lg ++ ){
        for(int i = 0 ; i < n; i ++ ){
            if(i + (1 << lg) - 1 < n){
                tab[lg][i] = max(tab[lg-1][i], tab[lg-1][i + (1 << (lg - 1))]);
            }
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    pii chk = get(C, D);
    pii bins = get(B, C - 1);
    if(bins.fi > chk.fi) return -1;
    int cur = B;
    int tr;
    for(int go = LOG - 1; go >= 0 ; go -- ){
        tr = cur - (1 << go);
        if(tr >= A){
            bins = get(tr, C - 1);
            if(bins.fi < chk.fi)
                cur = tr;
        }
    }
    pii ash = get(cur, B);
    B = ash.se;
    int moves = 0;
    while(1){
        if(rig[B] >= C){
            B = rig[B];
            moves ++ ;
            break;
        }
        if(lef[B] == -1 || H[lef[B]] > chk.fi) {
            B = rig[B];
            moves ++ ;
            continue;
        }
        if(H[lef[B]] > H[rig[B]]){
            B = lef[B];
            moves ++ ;
        }
        else{
            B = rig[B];
            moves ++ ;
        }
    }
    return moves;
}

• 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