Submission #127683

#	Time	Username	Problem	Language	Result	Execution time	Memory
127683		Utaha	Railway Trip (JOI17_railway_trip)	C++14	20 / 100	2067 ms	9328 KiB

railway_trip

/*input
15 5 15
5
4
1
2
3
1
1
2
4
5
4
1
5
3
5
8 1
11 1
5 3
6 11
9 12
15 14
15 2
3 12
2 1
4 8
15 5
12 6
1 13
13 8
14 9
*/
#include <bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pdd;
#define IOS ios_base::sync_with_stdio(0); cin.tie(0)
#define ALL(a) a.begin(),a.end()
#define SZ(a) ((int)a.size())
#define F first
#define S second
#define REP(i,n) for(int i=0;i<((int)n);i++)
#define pb emplace_back
#define MP(a,b) make_pair(a,b)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
    out<<'('<<P.F<<','<<P.S<<')';
    return out;
}

//}}}
const ll maxn=100005;
const ll maxlg=__lg(maxn)+2;
const ll INF64=8000000000000000000LL;
const int INF=0x3f3f3f3f;
const ll MOD=ll(1e9+7);
const ld PI=acos(-1);
const ld eps=1e-9;
//const ll p=880301;
//const ll P=31;

ll mypow(ll a,ll b){
    ll res=1LL;
    while(b){
        if(b&1) res=res*a%MOD;
        a=a*a%MOD;
        
        b>>=1;
    }
    return res;
}

int n;
int a[maxn];

vector<int> edge[maxn];
vector<pii> st;

vector<int> q;
int pt=0;
int d[maxn];
int bfs(int u,int v){
    REP(i,n) d[i]=-1;
    q.clear();
    pt=0;
    q.pb(u);
    d[u]=0;
    while(pt<SZ(q)){
        int cur=q[pt++];
        for(int nxt:edge[cur]) if(d[nxt]==-1){
            d[nxt]=d[cur]+1;
            q.pb(nxt);
        }
    }
    return d[v];
}

int main(){
    IOS;
    int k,q;
    cin>>n>>k>>q;
    REP(i,n) cin>>a[i];
    REP(i,n){
        while(SZ(st)&&a[i]>st.back().F) st.pop_back();
        if(SZ(st)){
            edge[i].pb(st.back().S);
            edge[st.back().S].pb(i);
            // cout<<i<<' '<<st.back().S<<'\n';
        }
        st.pb(a[i],i);
    }
    st.clear();
    for(int i=n-1;i>=0;i--){
        while(SZ(st)&&a[i]>st.back().F) st.pop_back();
        if(SZ(st)){
            edge[i].pb(st.back().S);
            edge[st.back().S].pb(i);
        }
        st.pb(a[i],i);
    }

    REP(i,q){
        int u,v;
        cin>>u>>v;
        u--;v--;
        cout<<bfs(u,v)-1<<'\n';
    }

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 25
• Subtask 4: 0 / 55