Submission #758584

#	Time	Username	Problem	Language	Result	Execution time	Memory
758584		KN200711	Race (IOI11_race)	C++14	0 / 100	9 ms	14420 KiB

race

#include "race.h"
# include <bits/stdc++.h>
# define ll long long
# define fi first
# define se second
using namespace std;

set< pair<ll, int> > nw[200001];
vector< pair<ll, int> > edge[200001];
int ans = 1e9 + 11;
int KK;

void dfs(int a, int pr, ll v, int c) {
	nw[a].insert(make_pair(v, c));
	for(int k=0;k<edge[a].size();k++) {
		if(edge[a][k].fi == pr) continue;
		dfs(edge[a][k].fi, a, v + edge[a][k].se, c+1);
		if(nw[edge[a][k].fi].size() > nw[a].size()) swap(nw[a], nw[edge[a][k].fi]);
		for(auto p : nw[edge[a][k].fi]) {
			auto it = nw[a].lower_bound(make_pair(KK + 2ll * v - p.fi + 1, 0));
			if(it == nw[a].begin()) continue;
			it--;
			if(it->fi == KK + 2ll * v - p.fi) ans = min(ans, it->se + p.se - 2 * c);
		}
		for(auto p : nw[edge[a][k].fi]) {
			nw[a].insert(p);
		}
	}
}

int best_path(int N, int K, int H[][2], int L[]) {
	KK = K;
	for(int i=0;i<N;i++) {
		edge[i].clear();
		nw[i].clear();
	}
	for(int i=0;i<N-1;i++) {
		edge[H[i][0]].push_back(make_pair(H[i][1], L[i]));
		edge[H[i][1]].push_back(make_pair(H[i][0], L[i]));
	}
	ans = 1e9 + 11;
	dfs(0, -1, 0, 0);
	if(ans == 1e9 + 11) return -1;
	return ans;
}

Compilation message (stderr)

race.cpp: In function 'void dfs(int, int, long long int, int)':
race.cpp:15:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |  for(int k=0;k<edge[a].size();k++) {
      |              ~^~~~~~~~~~~~~~~

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