Submission #1225098

#	Time	Username	Problem	Language	Result	Execution time	Memory
1225098		_rain_	Railway Trip (JOI17_railway_trip)	C++20	5 / 100	14 ms	3912 KiB

railway_trip

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;

const int N=(int)1e5;
const int INF=(int)1e9;
	int source[N+2],sink[N+2],l[N+2];
	int n,k,q;

int add(int a,int b){
		return (a+b>=n?a+b-n:a+b);
}
int sub(int a,int b){
	return a-b<0?a-b+n:a-b;
}

	vector<int>ke[N+2];
	void add_canh(int u,int v){
		ke[u].push_back(v);
	}
	
namespace subtask1{
	bool check(){
		return n<=100 && q<=100;
	}
	
	const int LIMIT=100;
	
	
	int vis[LIMIT+2];
	
	int process(int source,int sink){
		queue<int>q;
		for(int i=0;i<=n;++i) vis[i]=INF;
		q.push(source);
		vis[source]=1;
		while (q.size()){
			int u=q.front(); q.pop();
			for(auto&v:ke[u]){
				if (vis[v]==INF){
					vis[v]=vis[u]+1;
					q.push(v);
				}
			}
		}
		return vis[sink]-2;
		
	}
	
	void main_code(){
		for(int i=0;i<n;++i){
			int mx=0;
			for(int j=i+1;j<n;++j){
				if (mx+1>l[i]) break;
				if (l[j]>mx) {
					add_canh(i,j);
				}
				mx=max(mx,l[j]);
			}
			mx=0;
			for(int j=i-1;j>=0;--j){
				if (mx+1>l[i]) break;
				if (l[j]>mx) {
					add_canh(i,j);
				}
				mx=max(mx,l[j]);
			}
		}
		for(int i=1;i<=q;++i) cout<<min(process(source[i],sink[i]),process(sink[i],source[i]))<<'\n';
		return;
	}
}


int main(){
	ios::sync_with_stdio(false);
	cin.tie(0) ; cout.tie(0);
	#define task "main"
	if (fopen(task".inp","r")){
		freopen(task".inp","r",stdin);
		freopen(task".out","w",stdout);
	}
	
	cin>>n>>k>>q;
	for(int i=0;i<n;++i) cin>>l[i];	
	for(int i=1;i<=q;++i) {
		cin>>source[i]>>sink[i];
		--source[i] , --sink[i];
	}
	if (subtask1::check()){
		return subtask1::main_code(),0;
	}
	
	return 0;
}

Compilation message (stderr)

railway_trip.cpp: In function 'int main()':
railway_trip.cpp:80:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |                 freopen(task".inp","r",stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
railway_trip.cpp:81:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |                 freopen(task".out","w",stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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