Submission #984180

#	Time	Username	Problem	Language	Result	Execution time	Memory
984180		Alkaser_ID	Rainforest Jumps (APIO21_jumps)	C++17	4 / 100	666 ms	17212 KiB

jumps

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

bool sb1 = true;
int n, dp[200005], ad[200005], a[200005];
int nxup[200005],nxls[200005],lsup[200005];
void init(int N, std::vector<int> H) {
    n = N;
    for(int i=0;i<n;++i) a[i] = H[i];
    for(int i=1;i<n;++i){
        if(a[i] < a[i-1]) sb1 = false;
    }
    vector<pair<int,int>> v;
    for(int i=0;i<n;++i){
        v.push_back({H[i],i});
    }
    sort(v.begin(),v.end(),greater<pair<int,int>>());
    for(int i=0;i<n;++i) nxup[i] = nxls[i] = lsup[i] = -1;

    set<int> s;
    for(int i=0;i<n;++i) {
        if(!s.empty()){
            set<int>::iterator it= s.lower_bound(v[i].second);
            if(it != s.end()){
                nxup[v[i].second] = *it;
            }
            if(it != s.begin()){
                --it;
                lsup[v[i].second] = *it;
            }
        }
        s.insert(v[i].second);
    }

}

int minimum_jumps(int A, int B, int C, int D) {
    if(sb1) return C - B;
    if(A == B && C == D && false) {
        if(a[C] < a[B]) return -1;
        int res = 0;
        for(int cn = 0;;++cn){
            if(cn > 2 *n) {
                int vr = 5 / 0;
                return vr;
            }
            if(B == C) break;
            if(nxup[B] == -1 || B > C || B == -1) {res = -1; break;}
            ++res;
            int ls = lsup[B],nx = nxup[B];
            if(ls != -1) {
                if(a[ls] > a[nx] && a[ls] < a[C]) B = ls;
                else B = nx;
            }
            else B = nx;

        }
        return res;
    }

    int res = 1e9;

    for(int i= C;i <= D; ++i) dp[i] = 0;
    for(int i = A;i <= B; ++i) ad[i] = 0;
    for(int i=0;i < A; ++i) ad[i] = 1e9;
    for(int i=C-1;i>=0;i--){
        int nx = nxup[i];
        if(nx > D) dp[i] = 1e9;
        else dp[i] = dp[nx] + 1;
        if(i >= A && i <= B){
            res = min(res,dp[i]);
        }
        int ls = lsup[i];
        if(ls != -1){
            ad[ls] = min(ad[ls], ad[i] + 1);
        }
        else if(i< A){
            res = min(res,dp[i] + ad[i]);
        }
    }
    if(res >= 1e9) return -1;
    return res;
}

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

*/

Compilation message (stderr)

jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:45:28: warning: division by zero [-Wdiv-by-zero]
   45 |                 int vr = 5 / 0;
      |                          ~~^~~

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