제출 #741543

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
741543		myrcella	통행료 (IOI18_highway)	C++17	5 / 100	122 ms	7788 KiB

highway

//by szh
#include<bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}

#include "highway.h"

const int maxn = 9e4+10;

int fa[maxn];
bool mark[maxn];
bool ans[maxn];
vector <int> ww;
vector <pii> edge[maxn];
int dis,dif;
int ret[maxn];

void solve(vector <int> tmp,int cnt) {
	if (SZ(tmp)==1) {
		ans[tmp[0]] = 1;
		return;
	}
	vector <int> left;
	int mid = SZ(tmp)/2;
	rep(i,0,mid) ww[tmp[i]] = 1,left.pb(tmp[i]);
	int diss = ask(ww);
	rep(i,0,mid) ww[tmp[i]] = 0;
	vector <int> right;
	rep(i,mid,SZ(tmp)) right.pb(tmp[i]);
	if (diss>dis) solve(left,(diss-dis)/dif);
	if ((diss-dis)/dif<cnt) solve(right,cnt-(diss-dis)/dif);
}

bool dfs(int u,int lst,int rest) {
	if (rest==0) return true;
	vector <int> tmp;
	fa[u] = lst;
	int cnt = 0;
	for (pii v:edge[u]) {
		if (v.fi==lst) continue;
		tmp.pb(v.se);
		cnt++;
	}
	assert(cnt!=0);
	if (cnt==1) {
		for (pii v:edge[u]) {
			if (v.fi==lst) continue;
			dfs(v.fi,u,rest-1);
			ans[v.se] = 1;
		}
		return true;
	}
	solve(tmp,1);
	for (pii v:edge[u]) 
		if (v.fi!=lst and ans[v.se]==1) return dfs(v.fi,u,rest-1);
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
	rep(i,0,N-1) {
		edge[U[i]].pb({V[i],i});
		edge[V[i]].pb({U[i],i});
	}
	rep(i,1,N) ww.pb(0);
  dis = ask(ww);
  dif = B-A;
  dfs(0,-1,dis/A);
  rep(i,0,N-1) if (ans[i]) ret[U[i]]++,ret[V[i]]++;
  int u=-1,v=-1;
  rep(i,0,N) if (ret[i]==1) {
	  if (u==-1) u = i;
	  else v = i;
  }
  answer(u,v);
}

컴파일 시 표준 에러 (stderr) 메시지

highway.cpp: In function 'bool dfs(int, int, int)':
highway.cpp:54:15: warning: control reaches end of non-void function [-Wreturn-type]
   54 |  vector <int> tmp;
      |               ^~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31