Submission #983083

#	Time	Username	Problem	Language	Result	Execution time	Memory
983083		vjudge1	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	871 ms	74756 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
#define F(a,b) for(int a=0;a<b;a++)
#define M 1<<18
vector<int>adj[M];
int vis[M],d[M],n,h[M],e[M][20],f[M][20],st[M][20],loc[M];
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> S;
    F(i,N) loc[st[i+1][0]=h[i+1]=H[i]]=i+1;
    h[0]=1e9,n=N;
    F(j,19)for(int i=1;i+(1<<j+1)-2<n;i++)
        st[i][j+1]=max(st[i][j],st[i+(1<<j)][j]);
    F(i,N){
        while(S.size()&&H[S.top()]<=H[i]) S.pop();
        if(S.size()) adj[i+1].push_back(S.top()+1);
        S.push(i);
    }
    while(S.size())S.pop();
    for(int i=N;i--;){
        while(S.size()&&H[S.top()]<=H[i]) S.pop();
        if(S.size()) adj[i+1].push_back(e[i+1][0]=S.top()+1);
        S.push(i);
    }   
    for(int i=1;i<=N;i++)if(adj[i].size()>1)
        f[i][0]=adj[i][h[adj[i][0]]<=h[adj[i][1]]];
    else if(adj[i].size())
        f[i][0]=adj[i][0];
    F(j,19)for(int i=1;i<=N;i++)
        e[i][j+1]=e[e[i][j]][j],f[i][j+1]=f[f[i][j]][j];
}
int calc(int a,int b,int c,int d){
    int ans=0;
    for(int i=20;i--;) if(h[f[a][i]]<=c)
        a=f[a][i],ans+=1<<i;
    if(h[f[a][0]]<=d)
        return ans+1+(f[a][0]<b&&e[a][0]<b);
    for(int i=20;i--;)
        if(e[a][i]<b&&e[a][i])
            a=e[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:17:31: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
   17 |     F(j,19)for(int i=1;i+(1<<j+1)-2<n;i++)
      |                              ~^~
jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:54:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   54 |         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