Submission #112526

#	Time	Username	Problem	Language	Result	Execution time	Memory
112526		nxteru	Race (IOI11_race)	C++14	100 / 100	588 ms	85672 KiB

race

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> P;
#define F first
#define S second
#define PB push_back
#define INF 1000000000
int n,k,vs[200005],w[200005],la[200005],ans=INF;
vector<P>g[200005];
map<int,int>m[200005];
void merge(int x,int y){
	if(m[vs[x]].size()<m[vs[y]].size())swap(x,y);
	int vx=vs[x],vy=vs[y];
	for(map<int,int>::iterator i=m[vy].begin();i!=m[vy].end();i++){
		if(m[vx].find(k-w[vx]-w[vy]-i->F)!=m[vx].end())ans=min(ans,m[vx][k-w[vx]-w[vy]-i->F]+i->S+la[vx]+la[vy]);
	}
	for(map<int,int>::iterator i=m[vy].begin();i!=m[vy].end();i++){
		int c=i->F-w[vx]+w[vy];
		if(m[vx].find(c)!=m[vx].end())m[vx][c]=min(m[vx][c],i->S-la[vx]+la[vy]);
		else m[vx][c]=i->S-la[vx]+la[vy];
	}
	vs[y]=vx;
}
void dfs(int v,int p){
	for(int i=0;i<g[v].size();i++){
		int u=g[v][i].F,l=g[v][i].S;
		if(u==p)continue;
		dfs(u,v);
		w[vs[u]]+=l;
		la[vs[u]]++;
		merge(v,u);
	}
}
int best_path(int N,int K,int H[][2],int L[]){
	n=N;
	k=K;
	for(int i=0;i<n-1;i++){
		int a=H[i][0],b=H[i][1],c=L[i];
		g[a].PB(P(b,c));
		g[b].PB(P(a,c));
	}
	for(int i=0;i<n;i++)vs[i]=i,m[i][0]=0;
	dfs(0,-1);
	if(ans==INF)return -1;
	else return ans;
}

Compilation message (stderr)

race.cpp: In function 'void dfs(int, int)':
race.cpp:25:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[v].size();i++){
              ~^~~~~~~~~~~~

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