제출 #1356082

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1356082		kokokai	Railway Trip (JOI17_railway_trip)	C++20	20 / 100	2095 ms	10816 KiB

railway_trip

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define task "text"
#define fi first
#define se second
#define int long long
const int N = 2e5+5;
vector<int> adj[N];
int L[N];
int d[N];
int n,k,q;
namespace subtask2{
    void solve(){
        vector<int> st;
        for(int i=1;i<=n;i++){
            while(!st.empty() && L[st.back()] < L[i]) st.pop_back();
            if(st.size()){
                adj[i].push_back(st.back());
                adj[st.back()].push_back(i);
            }
            st.push_back(i);
        }
        st.clear();
        for(int i=n;i>=1;i--){
            while(!st.empty() && L[st.back()] < L[i]) st.pop_back();
            if(st.size()){
                adj[i].push_back(st.back());
                adj[st.back()].push_back(i);
            }
            st.push_back(i);
        }
        while(q--){
            int a,b;
            cin>>a>>b;
            for(int i=1;i<=n;i++){
                d[i]=1e9;
            }
            d[a]=0;
            queue<int> q;
            q.push(a);
            while(!q.empty()){
                int u=q.front();
                q.pop();
                for(int v:adj[u]){
                    if(d[v]>d[u]+1){
                        d[v]=d[u]+1;
                        q.push(v);
                    }
                }
            }
            cout<<d[b]-1<<'\n';
        }
    }
}
signed main(){
    ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);

    if(fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
    }
    cin>>n>>k>>q;
    for(int i=1;i<=n;i++) cin>>L[i];
    subtask2::solve();
}

컴파일 시 표준 에러 (stderr) 메시지

railway_trip.cpp: In function 'int main()':
railway_trip.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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