Submission #1148627

#	Time	Username	Problem	Language	Result	Execution time	Memory
1148627		KluydQ	Valley (BOI19_valley)	C++20	23 / 100	179 ms	70096 KiB

valley

#include <bits/stdc++.h>
 
#define respagold ios_base::sync_with_stdio(0), cin.tie(0);
#define ll long long
#define int long long
#define int2 __int128_t
#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
#define FORR( i, x, n, d ) for( int i = x; i >= n; i -= d )
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x.size())
#define pb push_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define pii pair <int, int>
#define mkp make_pair
 
using namespace std;
 
const int N = 3e5 + 123;
const int inf = 2e18;
const int MOD1 = 1e9 + 7;
const int MOD = 998244353;
const int P = 6547;
 
int a[N], b[N], n, m, q, x, y, z, w[N], s, e;
vector <int> shop;
pii edge[N];
 
mt19937 rng( chrono::steady_clock::now().time_since_epoch().count());
 
int rand( int l, int r )
{
    uniform_int_distribution <int> uid( l, r );
    return uid( rng );
}
vector <pii> g[N];
int tin[N], tout[N], tim, d[N], dd[N], up[N][20], dis[N][20], dp[N][20];

void dfs( int v, int p = 0, int ds = 0 )
{
	tin[v] = ++ tim;

	for( auto to : g[v] )
	{
		if( to.F == p ) continue;
		
		d[to.F] = d[v] + 1;
		dfs( to.F, v, to.S );
		dd[v] = min( dd[v], dd[to.F] + to.S );
	}
	tout[v] = tim;
}
void dfs1( int v, int p = 0, int ds = 0 )
{
	up[v][0] = p;
	dis[v][0] = ds;
	dp[v][0] = ds + dd[p];
	
	FOR( i, 1, 20, 1 )
	{
		up[v][i] = up[up[v][i - 1]][i - 1];
		dis[v][i] = dis[v][i - 1] + dis[up[v][i - 1]][i - 1];
		dp[v][i] = min( dp[v][i - 1], dp[up[v][i - 1]][i - 1] + dis[v][i - 1] );
	}
	for( auto to : g[v] )
	{
		if( to.F == p ) continue;
		dfs1( to.F, v, to.S );
	}
}
void solve()
{
	cin >> n >> s >> q >> e;
	
	FOR( i, 1, n, 1 ) dd[i] = inf;
	
	FOR( i, 1, n - 1, 1 )
	{
		cin >> x >> y >> z;
		edge[i] = { x, y };
		
		g[x].pb({ y, z });
		g[y].pb({ x, z });
	}
	FOR( i, 1, s, 1 )
	{
		cin >> x;
		shop.pb(x);
		dd[x] = 0;
	}
	dfs(e);
	dfs1(e);
	
	FOR( i, 1, n - 1, 1 ) if( d[edge[i].F] > d[edge[i].S] ) swap( edge[i].F, edge[i].S );
	
	FOR( i, 1, q, 1 )
	{
		cin >> x >> y;
		
		int v, u; tie( v, u ) = edge[x];
		
		if( tin[u] > tin[y] || tout[u] < tout[y] )
		{
			cout << "escaped\n";
			continue;
		}
		int dist = d[y] - d[u], ans = dd[y];
		
		FORR( j, 20, 0, 1 )
		{
			if( (dist >> j) & 1 ) ans = min( ans, dp[y][j] ), y = up[y][j];
		}
		if( ans == inf ) cout << "oo\n";
		else cout << ans << '\n';
	}
}
signed main() 
{
//	freopen("connect.in", "r", stdin);
//	freopen("connect.out", "w", stdout);
	    
    respagold
    
    int test = 1;
    
    if( !test ) cin >> test;
	
	while( test -- )
	{
		solve();
	}
}
// solved by KluydQ  

Compilation message (stderr)

valley.cpp: In function 'void dfs1(long long int, long long int, long long int)':
valley.cpp:66:26: warning: iteration 19 invokes undefined behavior [-Waggressive-loop-optimizations]
   66 |                 dp[v][i] = min( dp[v][i - 1], dp[up[v][i - 1]][i - 1] + dis[v][i - 1] );
      |                 ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:7:45: note: within this loop
    7 | #define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
      |                                             ^
valley.cpp:62:9: note: in expansion of macro 'FOR'
   62 |         FOR( i, 1, 20, 1 )
      |         ^~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 27
• Subtask 3: 23 / 23
• Subtask 4: 0 / 41