Submission #172380

#	Time	Username	Problem	Language	Result	Execution time	Memory
172380		cgiosy	Race (IOI11_race)	C++17	0 / 100	5 ms	376 KiB

race

#include "race.h"
#include <bits/stdc++.h>
#define rep(i,x,n) for(int i=x; i<n; i++)
using namespace std;
constexpr int INF=0x3f3f3f3f;

int best_path(int N, int K, int H[][2], int L[]) {
	int m=INF;
	vector<bool> V(N);
	vector<int> C(N, 1), D(K+1, INF), P(N, -1), X;
	vector<vector<pair<int, int>>> G(N);
	rep(i, 0, N-1) {
		int x=H[i][0], y=H[i][1], z=L[i];
		G[x].push_back({y, z});
		G[y].push_back({x, z});
	}
	#define ITER(i) for(auto[j,w]:G[i]) if(j!=P[i] && !V[j])
	function<void(int)> cnt=[&](int i) {
		ITER(i) P[j]=i, cnt(j), C[i]+=C[j];
	};
	function<int(int, int)> cent=[&](int i, int n) {
		ITER(i) if(C[j]>n/2) {
			P[i]=j;
			C[j]+=C[i]-=C[j];
			return cent(j, n);
		}
		return i;
	};
	function<void(int, int, int)> f=[&](int i, int d, int k) {
		X.push_back(d);
		m=min(m, k+D[K-d]);
		ITER(i) if(d+w<=K && k+1<m)
			f(j, d+w, k+1);
		D[d]=min(D[d], k);
	};
	function<void(int, int)> cd=[&](int i, int p) {
		P[i=cent(i, C[i])]=p;
		fill(begin(D), end(D), INF);
		V[i]=true;
		f(i, 0, 0);
		for(int x:X) D[x]=INF;
		for(auto[j,w]:G[i]) if(j!=P[i]) cd(j, i);
	};
	cnt(0);
	cd(0, -1);
	return (m==INF?-1:m);
}

Compilation message (stderr)

race.cpp: In lambda function:
race.cpp:17:30: warning: unused variable 'w' [-Wunused-variable]
  #define ITER(i) for(auto[j,w]:G[i]) if(j!=P[i] && !V[j])
                              ^
race.cpp:19:3: note: in expansion of macro 'ITER'
   ITER(i) P[j]=i, cnt(j), C[i]+=C[j];
   ^~~~
race.cpp: In lambda function:
race.cpp:17:30: warning: unused variable 'w' [-Wunused-variable]
  #define ITER(i) for(auto[j,w]:G[i]) if(j!=P[i] && !V[j])
                              ^
race.cpp:22:3: note: in expansion of macro 'ITER'
   ITER(i) if(C[j]>n/2) {
   ^~~~
race.cpp: In lambda function:
race.cpp:42:15: warning: unused variable 'w' [-Wunused-variable]
   for(auto[j,w]:G[i]) if(j!=P[i]) cd(j, i);
               ^

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57