Submission #3226578

---

Source Code Expand

#include <bits/stdc++.h>

using namespace std ;

#define N 500010
#define inf 0x3f3f3f3f
#define int long long 

struct node {
	int to , nxt , belong ;
}e[ N << 2 ];

int n , m ; 
int head[ N << 2 ] , cnt ;
int d[ N * 2 ] , vis[ N * 2 ] ;
int q[ N * 10 ] ;

void ins( int u , int v , int c ) {
	e[ ++ cnt ].to = v ;
	e[  cnt ].nxt = head[ u ] ;
	e[ cnt ].belong = c ;
	head[ u ] = cnt ;
}

std::set< int > st[ N ] ;

void spfa() {
	memset( d , inf , sizeof( d ) ) ;
	q[ 1 ] = vis[ 1 ] = 1 ;
	d[ 1 ] = 0 ;
	int l = 1 , r = 2 ;
	while( l < r ) {
		int u = q[ l ++ ] ;
		vis[ u ] = 0 ;
		for( int i = head[ u ] ; i ; i = e[ i ].nxt ) {
			int v = e[ i ].to , num = d[ u ] + ( !st[ u ].count( e[ i ].belong ) ) ;
			if( d[ v ] > num ) {
				d[ v ] = num ;
				st[ v ].clear() ;
				st[ v ].insert( e[ i ].belong ) ;
				if( ! vis[ v ] ) vis[ v ] = 1 , q[ r ++ ] = v ;
			}else if( d[ v ] == num ) {
				st[ v ].insert( e[ i ].belong ) ;
			}
		}
	}
	if( d[ n ] == inf ) puts( "-1" ) ;
	else printf( "%lld\n" , d[ n ] ) ;
}

main() {
	scanf( "%lld%lld" , &n ,&m ) ;
	for( int i = 1 ; i <= m ; i ++ ) {
		int x , y , c ;
		scanf( "%lld%lld%lld" , &x , &y , &c ) ;
		ins( x , y , c ) ;
		ins( y , x , c ) ;
	}
	spfa() ;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:52:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf( "%lld%lld" , &n ,&m ) ;
                               ^
./Main.cpp:55:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf( "%lld%lld%lld" , &x , &y , &c ) ;
                                          ^

Judge Result