Submission #2901904

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Source Code Expand

#include <bits/stdc++.h>
#define L long long

using namespace std;

L n,m,k,ans,cnt;

L c[100010];

vector<L>colors[100010];

L bu[100010],lev[100010];

L fin(L x){
	return x==bu[x]?x:bu[x]=fin(bu[x]);
}

struct S{
	L s,e,len;
}a[100010];

bool operator<(S a,S b){
	return a.len<b.len;
}

void uni(L x,L y){
	x=fin(x);
	y=fin(y);
	if(x==y) return;
	if(lev[x]<lev[y]) swap(x,y);
	bu[y]=x;
	if(lev[x]==lev[y]) lev[x]++;
}

int main()
{
	scanf("%lld %lld %lld",&n,&m,&k);
	L i,j;
	for(i=1;i<=n;i++)
	{
		scanf("%lld",&c[i]);
		colors[c[i]].push_back(i);
		
		bu[i]=i;
	}
	for(i=1;i<=k;i++)
	{
		for(j=1;j<colors[i].size();j++)
		{
			uni(colors[i][j],colors[i][j-1]);
			//printf("%lld %lld\n",colors[i][j],colors[i][j-1]);
		}
	}
	for(i=1;i<=m;i++)
	{
		scanf("%lld %lld %lld",&a[i].s,&a[i].e,&a[i].len);
	}
	sort(a+1,a+m+1);
	for(i=1;i<=m;i++)
	{
		//if(c[a[i].s]&&c[a[i].e])
		{
			if(fin(a[i].s)!=fin(a[i].e))
			{
				cnt++;
				ans+=a[i].len;
				uni(a[i].s,a[i].e);	
			}
		}
	}
	if(cnt<k-1) puts("-1");
	//printf("%lld ",cnt);
	else printf("%lld",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:37:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld %lld",&n,&m,&k);
                                  ^
./Main.cpp:41:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&c[i]);
                      ^
./Main.cpp:56:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld %lld %lld",&a[i].s,&a[i].e,&a[i].len);
                                                    ^

Judge Result