제출 #423444

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
423444		codebuster_10	경주 (Race) (IOI11_race)	C++17	100 / 100	485 ms	83776 KiB

race

#include <bits/stdc++.h>

using namespace std ;

//#define int int64_t //be careful about this 
#define endl "\n"
#define f(i,a,b) for(int i=int(a);i<int(b);++i)

#define pr pair
#define ar array
#define fr first
#define sc second
#define vt vector
#define pb push_back
#define eb emplace_back
#define LB lower_bound  
#define UB upper_bound
#define PQ priority_queue

#define sz(x) ((int)(x).size())
#define all(a) (a).begin(),(a).end()
#define allr(a) (a).rbegin(),(a).rend()
#define mem(a,b) memset(a, b, sizeof(a))

template<class A> void rd(vt<A>& v);
template<class T> void rd(T& x){ cin >> x; }
template<class H, class... T> void rd(H& h, T&... t) { rd(h) ; rd(t...) ;}
template<class A> void rd(vt<A>& x) { for(auto& a : x) rd(a) ;}

template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

template<typename T>
void __p(T a) {
  cout<<a; 
}
template<typename T, typename F>
void __p(pair<T, F> a) {
  cout<<"{";
  __p(a.first);
  cout<<",";
  __p(a.second);
  cout<<"}\n"; 
}
template<typename T>
void __p(std::vector<T> a) {
  cout<<"{";
  for(auto it=a.begin(); it<a.end(); it++)
    __p(*it),cout<<",}\n"[it+1==a.end()]; 
}
template<typename T, typename ...Arg>
void __p(T a1, Arg ...a) {
  __p(a1);
  __p(a...);
}
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
  cout<<name<<" : ";
  __p(arg1);
  cout<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
  int bracket=0,i=0;
  for(;; i++)
    if(names[i]==','&&bracket==0)
      break;
    else if(names[i]=='(')
      bracket++;
    else if(names[i]==')')
      bracket--;
  const char *comma=names+i;
  cout.write(names,comma-names)<<" : ";
  __p(arg1);
  cout<<" | ";
  __f(comma+1,args...);
}

void setIO(string s = "") {
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); 
  cin.exceptions(cin.failbit); 
	cout.precision(15);	cout << fixed;
  if(sz(s)){
  	freopen((s+".in").c_str(),"r",stdin);
  	freopen((s+".out").c_str(),"w",stdout);
  }
}





























int best_path(int N, int K, int H[][2], int L[])	{
	vt<ar<int,2>> g[N];
	f(i,0,N-1){
		int u = H[i][0], v = H[i][1], w = L[i];
		g[u].pb({v,w});
		g[v].pb({u,w});
	}
	
	
	int ans = N;
	
	map<int,int> dp[N];
	vt<int> ew(N), el(N);	/* current dp[i] is actually {a + extra_weight, b + extra_length} */
	
	function<void(int,int)> dfs = [&](int i,int p){
		dp[i][0] = ew[i] = el[i] = 0;
		for(auto [j,w] : g[i]) if(j != p){
			dfs(j,i);
			if(sz(dp[i]) > sz(dp[j])){
				
				
				// update ans.
				for(auto [w_j, l_j] : dp[j]){
					int actual_w = w_j + ew[j] + w;
					int actual_l = l_j + el[j] + 1;
					int need_w = K - actual_w;
					int put_i = need_w - ew[i];
					if(dp[i].count(put_i)){
						ckmin(ans,dp[i][put_i] + el[i] + actual_l);
					}
				}
				
				// update dp[i].
				for(auto [w_j, l_j] : dp[j]){
					int actual_w = w_j + ew[j] + w;
					int actual_l = l_j + el[j] + 1;
					int put_i = actual_w - ew[i];
					int put_l = actual_l - el[i];
					if(dp[i].count(put_i)){
						ckmin(dp[i][put_i], put_l);
					}else{
						dp[i][put_i] = put_l;
					}
				}
				
				dp[j].clear();
			}else{
				
				// update ans.
				for(auto [w_i,l_i] : dp[i]){
					int actual_w = w_i + ew[i] + w;
					int actual_l = l_i + el[i] + 1;
					int need_w = K - actual_w;
					int put_j = need_w - ew[j];
					if(dp[j].count(put_j)){
						ckmin(ans,dp[j][put_j] + el[j] + actual_l);
					}
				}
				
				//update dp[j].
				el[j] += 1;
				ew[j] += w;
				for(auto [w_i,l_i] : dp[i]){
					int actual_w = w_i + ew[i];
					int actual_l = l_i + el[i];
					int put_j = actual_w - ew[j];
					int put_l = actual_l - el[j];
					if(dp[j].count(put_j)){
						ckmin(dp[j][put_j],put_l);
					}else{
						dp[j][put_j] = put_l;
					}
				}
				
				// swap
				dp[i].swap(dp[j]);
				dp[j].clear();
				ew[i] = ew[j];
				el[i] = el[j];
	
			}
		}
		
		
		
	};
	dfs(0,0);
	if(ans == N) ans = -1;
	return ans;
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	

}

/*
#include <stdio.h>
#include <stdlib.h>

#define MAX_N 500000

static int N, K;
static int H[MAX_N][2];
static int L[MAX_N];
static int solution;

inline 
void my_assert(int e) {if (!e) abort();}

void read_input()
{
  int i;
  my_assert(2==scanf("%d %d",&N,&K));
  for(i=0; i<N-1; i++)
    my_assert(2==scanf("%d %d",&H[i][0],&H[i][1]));
  for(i=0; i<N-1; i++)
    my_assert(1==scanf("%d",&L[i]));
  my_assert(1==scanf("%d",&solution));
}

int main()
{
  int ans;
  read_input();
  ans = best_path(N,K,H,L);
  if(ans==solution)
    printf("Correct.\n");
  else
    printf("Incorrect. Returned %d, Expected %d.\n",ans,solution);

  return 0;
}







3 3
0 1
1 2
1
1
-1



11 12
0 1
0 2
2 3
3 4
4 5
0 6
6 7
6 8
8 9
8 10
3
4
5
4
6
3
2
5
6
7
2

*/

컴파일 시 표준 에러 (stderr) 메시지

race.cpp: In function 'void setIO(std::string)':
race.cpp:84:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |    freopen((s+".in").c_str(),"r",stdin);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:85:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |    freopen((s+".out").c_str(),"w",stdout);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57