Submission #542020

#	Time	Username	Problem	Language	Result	Execution time	Memory
542020		Pherokung	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1153 ms	50504 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define F first
#define S second
typedef pair<int,int> pa;

int n,h[200005],l[200005][20],r[200005][20],mx[200005][20];
stack<int> stk;

void init(int N, vector<int> H) {
    n = N;
    for(int i=0;i<N;i++) h[i+1] = H[i];
    h[n+1] = -1;
    h[0] = -1;

    for(int i=1;i<=n;i++){
        while(!stk.empty()){
            if(h[stk.top()] < h[i]) stk.pop();
            else break;
        }
        if(stk.empty()) l[i][0] = -1;
        else l[i][0] = stk.top();
        stk.push(i);
    }
    while(!stk.empty()) stk.pop();

    for(int i=n;i>=1;i--){
        while(!stk.empty()){
            if(h[stk.top()] < h[i]) stk.pop();
            else break;
        }
        if(stk.empty()) r[i][0] = -1;
        else r[i][0] = stk.top();
        stk.push(i);
    }
    while(!stk.empty()) stk.pop();

    for(int i=1;i<=n;i++){
        if(l[i][0] == -1) mx[i][0] = r[i][0];
        else if(r[i][0] == -1) mx[i][0] = l[i][0];
        else if(h[l[i][0]] > h[r[i][0]]) mx[i][0] = l[i][0];
        else if(h[l[i][0]] < h[r[i][0]]) mx[i][0] = r[i][0];
    }

    for(int i=1;i<=18;i++){
        for(int j=1;j<=n;j++){
            if(l[j][i-1] == -1) l[j][i] = -1;
            else l[j][i] = l[l[j][i-1]][i-1];
            if(r[j][i-1] == -1) r[j][i] = -1;
            else r[j][i] = r[r[j][i-1]][i-1];
            if(mx[j][i-1] == -1) mx[j][i] = -1;
            else mx[j][i] = mx[mx[j][i-1]][i-1];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    A++, B++, C++, D++;
    int pos = B,ans = 0;

    for(int i=18;i>=0;i--){
        if(l[pos][i] == -1) continue;
        if(l[pos][i] >= A && r[l[pos][i]][0] <= D && r[l[pos][i]][0] != -1){
            pos = l[pos][i];
        }
    }

    //printf(">>%d\n",pos);

    for(int i=18;i>=0;i--){
        if(mx[pos][i] == -1) continue;
       //printf("!!%d : %d %d\n",i,mx[pos][i],r[mx[pos][i]][0]);
        if(r[mx[pos][i]][0] != -1 && r[mx[pos][i]][0] < C){
            pos = mx[pos][i];
            ans += (1<<i);
        }
    }

    if(r[pos][0] != -1 && r[pos][0] < C && r[mx[pos][0]][0] <= D && r[mx[pos][0]][0] != -1){
        ans++;
        pos = mx[pos][0];
    }

    for(int i=18;i>=0;i--){
        if(r[pos][i] == -1) continue;
        if(r[pos][i] < C){
            pos = r[pos][i];
            ans += (1<<i);
        }
    }

    if(r[pos][0] > D || r[pos][0] == -1) return -1;
    else return ans+1;

}

/*
7 3
3 2 1 6 4 5 7
4 4 6 6
1 3 5 6
0 1 2 2
*/

• 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