Submission #110514

#	Time	Username	Problem	Language	Result	Execution time	Memory
110514		ckodser	007 (CEOI14_007)	C++14	0 / 100	497 ms	54264 KiB

007

#include<bits/stdc++.h>
#define pb push_back
using namespace std;
const int N = 200005;
int n, m, a, b, s1, s2, D[2][N], F[N], P[N];
vector < int > vec[N], Adj[N];
inline void BFS(int st, int w, int tp = 0)
{
	queue < int > qu;
	qu.push(st); D[w][st] = 0;
	while (qu.size())
	{
		int v = qu.front();
		qu.pop();
		if (tp) vec[D[w][v]].pb(v);
		for (int &u : Adj[v])
			if (D[w][u] == -1)
				D[w][u] = D[w][v] + 1, qu.push(u);
	}
}
inline bool Check(int s, int t)
{
	if (D[0][t] < D[0][s] || D[1][t] < D[1][s])
		return 0;
	if (D[0][s] < D[0][t] || D[1][s] < D[1][t])
		return 1;
	return (F[s] <= F[t]);
}
inline bool CMP(int i, int j)
{
	return (D[0][i] <= D[0][j]);
}
int main()
{
	scanf("%d%d%d%d%d%d", &n, &m, &s1, &s2, &a, &b);
	for (int i = 0; i < m; i++)
	{
		int v, u;
		scanf("%d%d", &v, &u);
		Adj[v].pb(u);
		Adj[u].pb(v);
	}
	memset(D, -1, sizeof(D));
	BFS(s2, 0, 1);
	memset(D, -1, sizeof(D));
	BFS(a, 0); BFS(b, 1);
	memset(F, 63, sizeof(F));
	for (int i = 1; i <= n; i++)
		P[i] = i;
	sort(P + 1, P + n + 1, CMP);
	for (int i = 1; i <= n; i++)
	{
		int v = P[i];
		if (D[0][v] == D[1][v])
		{
			F[v] = D[0][v];
			for (int u : Adj[v])
				if (D[0][v] == D[0][u] + 1 && D[1][v] == D[1][u] + 1)
					F[v] = min(F[v], F[u]);
		}
	}
	for (int i = 0; ; i ++)
		for (int v : vec[i])
			if (!Check(s1, v))
				return !printf("%d\n", i - 1);
	return 0;
}

Compilation message (stderr)

007.cpp: In function 'int main()':
007.cpp:35:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d%d%d", &n, &m, &s1, &s2, &a, &b);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
007.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &v, &u);
   ~~~~~^~~~~~~~~~~~~~~~

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