Submission #3229184

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <queue>
#include <cstdio>
#include <cstring>
using namespace std;
const int MAXN = 100005;
struct Edge{
	int to,next,w;
}e[MAXN<<3];
struct E{
	int u,v,c;
	bool operator < (const E &b)const
	{
		return c<b.c;
	}
}t[MAXN<<1];
int head[MAXN<<3],n,m,fa[MAXN],id[MAXN],sz;
bool vis[MAXN<<3];
int getan(int x)
{
	return x==fa[x]?x:fa[x]=getan(fa[x]);
}
int cnt=0;
inline void insert(int u,int v,int w)
{
	e[++cnt].to=v,e[cnt].next=head[u],head[u]=cnt,e[cnt].w=w;
}
inline void work(int l,int r)
{
	for(int i=l;i<=r;++i){
		vis[t[i].u]=vis[t[i].v]=id[t[i].u]=id[t[i].v]=0;
		fa[t[i].u]=t[i].u;
		fa[t[i].v]=t[i].v;
	}
	for(int i=l,x,y;i<=r;++i)
		x=getan(t[i].u),y=getan(t[i].v),fa[x]=y;
	for(int i=l,x,y;i<=r;++i){
		x=getan(t[i].u),y=getan(t[i].v);
		if(!vis[t[i].u]){
			if(!id[x])id[x]=++sz;
			insert(t[i].u,id[x],1);
			insert(id[x],t[i].u,1);
			vis[t[i].u]=1;
		}
		if(!vis[t[i].v]){
			if(!id[y])id[y]=++sz;
			insert(t[i].v,id[y],1);
			insert(id[y],t[i].v,1);
			vis[t[i].v]=1;
		}
	}
}
struct Node{
	int x,v;
	bool operator < (const Node &b)const
	{
		return v>b.v;
	}
};
priority_queue<Node>q;
int d[MAXN<<3];
inline void dij()
{
	memset(vis,0,sizeof(vis));
	memset(d,0x3f,sizeof(d));
	d[1]=0;
	q.push((Node){1,0});
	while(!q.empty()){
		Node x=q.top();
		q.pop();
		int u=x.x;
		if(vis[u])continue;
		vis[u]=true;
		for(int i=head[u];i;i=e[i].next){
			int v=e[i].to;
			if(d[v]>d[u]+e[i].w){
				d[v]=d[u]+e[i].w;
				q.push((Node){v,d[v]});
			}
		}
	}
	cout<<(d[n]==0x3f3f3f3f?-1:d[n])<<endl;
}
int que[MAXN<<3];
inline void bfs()
{
	memset(vis,0,sizeof(vis));
	int front=1,back=0;
	que[++back]=1,vis[1]=1;
	d[1]=0;
	d[n]=0x3f3f3f3f;
	while(front<=back){
		int u=que[front++];
		for(int i=head[u];i;i=e[i].next){
			int v=e[i].to;
			if(!vis[v]){
				d[v]=d[u]+1;
				que[++back]=v;
				vis[v]=1;
			}
		}
	}
	cout<<(d[n]==0x3f3f3f3f?-1:d[n]/2)<<endl;
}
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;++i){
		scanf("%d%d%d",&t[i].u,&t[i].v,&t[i].c);
	}
	sz=n;
	sort(t+1,t+m+1);
	int p=1;
	while(p<=m){
		int r=p;
		while(t[r+1].c==t[r].c)++r;
		work(p,r);
		p=r+1;
	}
//	dij();
	bfs();
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:108:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
./Main.cpp:110:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&t[i].u,&t[i].v,&t[i].c);
                                          ^

Judge Result