Submission #67155

#	Time	Username	Problem	Language	Result	Execution time	Memory
67155		hamzqq9	Balanced Tree (info1cup18_balancedtree)	C++14	23 / 100	593 ms	20140 KiB

balancedtree

#include<bits/stdc++.h>
#define st first
#define nd second
#define pb push_back
#define ppb pop_back
#define umax(x,y) x=max(x,y)
#define umin(x,y) x=min(x,y)
#define ll long long
#define ii pair<int,int>
#define iii pair<int,ii>
#define sz(x) ((int) x.size())
#define orta ((bas+son)>>1)
#define all(x) x.begin(),x.end()
#define dbgs(x) cerr<<(#x)<<" --> "<<(x)<<" "
#define dbg(x) cerr<<(#x)<<" --> "<<(x)<<endl;getchar()
#define pw(x) (1<<(x))
#define inf 2000000000
#define MOD 1000000007
#define N 100005
#define MAX 10000006
#define LOG 22
using namespace std;

int n,x,y,T;
int NE[N][2];
int ans,cev;
int c[N],temp[N];
vector<int> v[N];

void S3() {}

void NDFS(int node,int ata,int NEE[]) {

/*	printf("%d\n",node);

	for(int i=0;i<2;i++) printf("%d ",NEE[i]);

	printf("\n----------\n");*/

	int NEN[2];

	umax(ans,min(NEE[c[node]],NE[node][c[node]]));

	int mn[2][2]={NEE[0],inf,NEE[1],inf};

	swap(mn[c[node]][0],mn[c[node]][1]);

	mn[c[node]][0]=0;

	for(int i:v[node]) {

		if(i==ata) continue ;

		for(int j=0;j<2;j++) {

			if(NE[i][j]+1<mn[j][1]) {

				mn[j][1]=NE[i][j]+1;

				if(mn[j][1]<mn[j][0]) swap(mn[j][1],mn[j][0]);				

			}

		}

		if(1<mn[c[i]][1]) {

			mn[c[i]][1]=1;

			if(mn[c[i]][1]<mn[c[i]][0]) swap(mn[c[i]][1],mn[c[i]][0]);

		}

	}

	for(int i:v[node]) {

		if(i==ata) continue ;

		int t0=(c[i]==0?1:NE[i][0]+1);
		int t1=(c[i]==1?1:NE[i][1]+1);

		NEN[0]=(mn[0][0]==t0?mn[0][1]:mn[0][0])+1;
		NEN[1]=(mn[1][0]==t1?mn[1][1]:mn[1][0])+1;

		NDFS(i,node,NEN);

	}

}

void SDFS(int node,int ata) {

	NE[node][c[node]]=inf;

	NE[node][!c[node]]=inf;

	for(int i:v[node]) {

		if(i==ata) continue ;

		SDFS(i,node);

		umin(NE[node][0],NE[i][0]+1);

		if(c[i]==0) NE[node][0]=1;

		umin(NE[node][1],NE[i][1]+1);

		if(c[i]==1) NE[node][1]=1;


	}

//	printf("node-->%d ne0-->%d ne1-->%d\n",node,NE[node][0],NE[node][1]);

}

void back_track(int now) {

	if(now>n) {

		SDFS(1,0);

		int NE[2];

		NE[0]=NE[1]=inf;

		ans=0;

		NDFS(1,0,NE);

		if(cev>ans) {

			cev=ans;

			for(int i=1;i<=n;i++) temp[i]=c[i];

		}

		return ;

	}

	if(c[now]!=-1) back_track(now+1);
	else {

		c[now]=1;

		back_track(now+1);

		c[now]=0;

		back_track(now+1);

		c[now]=-1;

	}

}

void S2() {

	SDFS(1,0);

	int NE[2];

	NE[0]=NE[1]=inf;

	ans=0;

	NDFS(1,0,NE);

	if(ans==inf) {

		printf("-1\n");

		return ;

	}

	printf("%d\n",ans);

	for(int i=1;i<=n;i++) printf("%d ",c[i]);

	puts(""); 

}

void S1() {

	cev=inf;

	back_track(1);

	if(cev==inf) {

		printf("-1\n");

		return ;

	}

	printf("%d\n",cev);

	for(int i=1;i<=n;i++) printf("%d ",temp[i]);

	puts("");

}

bool is_path() {

	int leaf=0;

	for(int i=1;i<=n;i++) {

		if(sz(v[i])>2) return false;

		if(sz(v[i])==1) leaf++;

	}

	return (n==1 || leaf==2);

}

void read() {

	scanf("%d",&n);

	for(int i=1;i<n;i++) {

		scanf("%d %d",&x,&y);

		v[x].pb(y);
		v[y].pb(x);

	}

	for(int i=1;i<=n;i++) scanf("%d",&c[i]);

}

void clear() {

	for(int i=1;i<=n;i++) v[i].clear();

}

int main() {
 
//	freopen("input.txt","r",stdin);
 
	scanf("%d",&T);

	for(int t=1;t<=T;t++) {

		read();

		if(T<=500 && n<=17) S1();
		else if(is_path()) S3();
		else S2();

		clear();

	}


} 	

Compilation message (stderr)

balancedtree.cpp: In function 'void read()':
balancedtree.cpp:230:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
balancedtree.cpp:234:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~~
balancedtree.cpp:241:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++) scanf("%d",&c[i]);
                        ~~~~~^~~~~~~~~~~~
balancedtree.cpp: In function 'int main()':
balancedtree.cpp:255:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&T);
  ~~~~~^~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 0 / 26
• Subtask 4: 0 / 45
• Subtask 5: 0 / 6