Submission #983070

#	Time	Username	Problem	Language	Result	Execution time	Memory
983070		boyliguanhan	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	868 ms	64028 KiB

jumps

//viewed solution 
#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
vector<int>adj[200100];
int vis[200100],d[200100],n,h[200100],rbj[200100][20],obj[200100][20],st[200100][20],loc[200100];
vector<int> v;
int query(int a,int b){
    int x=31-__builtin_clz(b-a+1);
    return max(st[a][x],st[b-(1<<x)+1][x]);
}
void init(int N, std::vector<int> H) {
    stack<int> stk;
    for(int i=0;i<N;i++)
        loc[st[i+1][0]=h[i+1]=H[i]]=i+1;
    h[0]=1e9,n=N;
    for(int j=1;j<20;j++) for(int i=1;i+(1<<j)-2<n;i++)
        st[i][j]=max(st[i][j-1],st[i+(1<<j-1)][j-1]);
    for(int i=0;i<N;i++){
        while(stk.size()&&H[stk.top()]<=H[i])
            stk.pop();
        if(stk.size())
            adj[i+1].push_back(stk.top()+1);
        stk.push(i);
    }
    while(stk.size())stk.pop();
    for(int i=N;i--;){
        while(stk.size()&&H[stk.top()]<=H[i])   
            stk.pop();
        if(stk.size())
            adj[i+1].push_back(rbj[i+1][0]=stk.top()+1);
        stk.push(i);
    }   
    for(int i=1;i<=N;i++)if(adj[i].size()>1)
        obj[i][0]=adj[i][h[adj[i][0]]<=h[adj[i][1]]];
    else if(adj[i].size())
        obj[i][0]=adj[i][0];
    for(int j=1;j<20;j++)
        for(int i=1;i<=N;i++)
            rbj[i][j]=rbj[rbj[i][j-1]][j-1],
            obj[i][j]=obj[obj[i][j-1]][j-1];
}
int calc(int a,int b,int c,int d){
    int ans=0;
    for(int i=20;i--;) if(h[obj[a][i]]<=c)
        a=obj[a][i],ans+=1<<i;
    if(h[obj[a][0]]<=d)
        return ans+1+(obj[a][0]<b&&rbj[a][0]<b);
    for(int i=20;i--;)
        if(rbj[a][i]<b&&rbj[a][i])
            a=rbj[a][i],ans+=1<<i;
    return ans+1;
}
int minimum_jumps(int A, int B, int C, int D) {
    A++,B++,C++,D++;
    int m1=query(B,C-1),m2=query(C,D);
    if(m1>m2)
        return -1;
    int l=A,r=B;
    while(l<=r){
        int mid=l+r>>1;
        if(query(mid,B)<m2)
            A=mid,r=mid-1;
        else l=mid+1;
    }
    return calc(loc[query(A,B)],C,m1,m2);
}

Compilation message (stderr)

jumps.cpp: In function 'void init(int, std::vector<int>)':
jumps.cpp:18:43: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   18 |         st[i][j]=max(st[i][j-1],st[i+(1<<j-1)][j-1]);
      |                                          ~^~
jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:61:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   61 |         int mid=l+r>>1;
      |                 ~^~

• 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