Submission #2168836

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Source Code Expand

#include<cstdio>
#include<algorithm>
#include<cstring>
#define ll long long 
struct r{
	int u,v,w;
}e[400050];
int w[200050],fa[200050],cnt,n,m;
ll ans;
int get_fa(int u){return fa[u]==u ? u:fa[u]=get_fa(fa[u]);}
bool cmp(r a,r b){return a.w<b.w;}
int main(){
	scanf("%d%d",&n,&m);
	memset(w,127,sizeof w);
	for (int i=1;i<=m;i++){
		scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
		w[e[i].u]=std::min(w[e[i].u],e[i].w+1);
		w[e[i].v]=std::min(w[e[i].v],e[i].w+2);
	}
	for (int i=0;i<n;i++) fa[i]=i;
	for (int i=1;i<(n<<1);i++)
		w[i]=std::min(w[i],w[i-1]+2);
	for (int i=0;i<n;i++)
		e[++m]=(r){i,(i+1)%n,std::min(w[i],w[i+n])};
	std::sort(e+1,e+m+1,cmp);
	for (int i=1;i<=m;i++){
		if ((u=get_fa(e[i].u))==(v=get_fa(e[i].v))) continue;
		fa[v]=u;
		ans+=1ll*e[i].w;
		cnt++;
		if (cnt==n-1) {
			printf("%lld",ans);
			return 0;
		}
	}
} 

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:27:8: error: ‘u’ was not declared in this scope
   if ((u=get_fa(e[i].u))==(v=get_fa(e[i].v))) continue;
        ^
./Main.cpp:27:28: error: ‘v’ was not declared in this scope
   if ((u=get_fa(e[i].u))==(v=get_fa(e[i].v))) continue;
                            ^
./Main.cpp:28:6: error: ‘v’ was not declared in this scope
   fa[v]=u;
      ^
./Main.cpp:28:9: error: ‘u’ was not declared in this scope
   fa[v]=u;
         ^
./Main.cpp:13:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
./Main.cpp:16:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
                                          ^