Submission #126513

#	Time	Username	Problem	Language	Result	Execution time	Memory
126513		baluteshih	Railway Trip (JOI17_railway_trip)	C++14	20 / 100	2053 ms	8688 KiB

railway_trip

#include <bits/stdc++.h>
#define jizz ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define pb push_back
#define MP make_pair
#define F first
#define S second
#define MEM(i,j) memset(i,j,sizeof i)
#define ALL(v) v.begin(),v.end()
#define ET cout << "\n"
#define DB(a,s,e) {for(int i=s;i<e;++i) cout << a[i] << " ";ET;}
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

vector<int> G[100005];
int val[100005];
vector<int> st;
queue<int> qu;
int dis[100005];

int main()
{jizz
	int n,k,q,a,b;
	cin >> n >> k >> q;
	for(int i=1;i<=n;++i)
		cin >> val[i];
	for(int i=1;i<=n;++i)
	{
		while(!st.empty()&&val[i]>val[st.back()]) st.pop_back();
		if(!st.empty())
			if(val[st.back()]==val[i])
				G[i].pb(st.back()),G[st.back()].pb(i),st.back()=i;
			else
				G[i].pb(st.back()),G[st.back()].pb(i),st.pb(i);
		else
			st.pb(i);
	}
	st.clear();
	for(int i=n;i>0;--i)
	{
		while(!st.empty()&&val[i]>val[st.back()]) st.pop_back();
		if(!st.empty())
			if(val[st.back()]==val[i])
				G[i].pb(st.back()),G[st.back()].pb(i),st.back()=i;
			else
				G[i].pb(st.back()),G[st.back()].pb(i),st.pb(i);
		else
			st.pb(i);
	}
	while(q--)
	{
		cin >> a >> b,fill(dis+1,dis+n+1,n+1);
		while(!qu.empty()) qu.pop();
		qu.push(a),dis[a]=0;
		while(!qu.empty())
		{
			int u=qu.front();
			qu.pop();
			if(u==b) break;
			for(int i:G[u])
				if(dis[i]>dis[u]+1)
					dis[i]=dis[u]+1,qu.push(i);
		}
		cout << dis[b]-1 << "\n";
	}
}

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