Submission #727492

#	Time	Username	Problem	Language	Result	Execution time	Memory
727492		n0sk1ll	007 (CEOI14_007)	C++17	0 / 100	596 ms	33372 KiB

007

#include <bits/stdc++.h>

#define FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define all(x) x.begin(),x.end()
#define ff(i,a,b) for (int i = a; i < b; i++)
#define fff(i,a,b) for (int i = a; i <= b; i++)
#define bff(i,a,b) for (int i = b-1; i >= a; i--)
#define bfff(i,a,b) for (int i = b; i >= a; i--)

using namespace std;
long double typedef ld;
unsigned int typedef ui;
long long int typedef li;
pair<int,int> typedef pii;
pair<li,li> typedef pli;
pair<ld,ld> typedef pld;
vector<vector<int>> typedef graph;
unsigned long long int typedef ull;
//const int mod = 998244353;
const int mod = 1000000007;







//Note to self: Check for overflow

graph g(200005);
bool vis[200005];

vector<int> njeni[200005],njegovi[200005];

bool moze(int n, int ona, int on, int a, int b, int wait)
{
    fff(i,1,n) vis[i]=false;

    queue<pii> bfs;
    bfs.push({on,wait});
    while (!bfs.empty())
    {
        auto [p,d]=bfs.front(); bfs.pop();
        if (vis[p]) continue; vis[p]=true; //cout<<p<<" ";
        if (d==0) continue;
        for (auto it : g[p]) bfs.push({it,d-1});
    }

    if (vis[a]) return false;
    if (vis[b]) return false;

    ff(i,0,n) njeni[i].clear(),njegovi[i].clear();
    fff(i,1,n) if (vis[i]) njegovi[0].pb(i);
    njeni[0].pb(ona);

    fff(i,1,n) vis[i]=false;

    ff(dubina,0,n)
    {
        for (auto p : njeni[dubina])
        {
            if (vis[p]) continue;
            vis[p]=1;
            for (auto it : g[p]) njeni[dubina+1].pb(it);
        }

        for (auto p : njegovi[dubina])
        {
            if (vis[p]) continue;
            vis[p]=1;
            if (p==a) return false;
            if (p==b) return false;
            for (auto it : g[p]) njegovi[dubina+1].pb(it);
        }
    }

    return true;

}

int main()
{
    FAST;

    int n,m; cin>>n>>m;
    int ona,on,a,b; cin>>ona>>on>>a>>b;
    while (m--)
    {
        int u,v; cin>>u>>v;
        g[u].pb(v),g[v].pb(u);
    }

    int l=-1,r=n;
    while (r-l>1)
    {
        int mid=(l+r)/2;
        if (moze(n,ona,on,a,b,mid)) l=mid;
        else r=mid;
    }

    cout<<l<<"\n";
}

//Note to self: Check for overflow

Compilation message (stderr)

007.cpp: In function 'bool moze(int, int, int, int, int, int)':
007.cpp:51:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   51 |         if (vis[p]) continue; vis[p]=true; //cout<<p<<" ";
      |         ^~
007.cpp:51:31: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   51 |         if (vis[p]) continue; vis[p]=true; //cout<<p<<" ";
      |                               ^~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70