Submission #3229439

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Source Code Expand

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <memory.h>
#include <math.h>
#include <assert.h>
#include <queue>
#include <map>
#include <set>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <unordered_map>
#include <random>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define Fi first
#define Se second
#define pb(x) push_back(x)
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()

int N,M;
vector<int> out[100500], in[100500];
int from[500500], to[500500], c[500500];
int dist[500500];
int main(){
	scanf("%d%d",&N,&M);
	for(int i=1;i<=M;i++){
		int x,y,z; scanf("%d%d%d",&x,&y,&z);
		from[i*2-1] = x; to[i*2-1] = y; c[i*2-1] = z;
		from[i*2] = y; to[i*2] = x; c[i*2] = z;
		out[x].push_back(i*2-1); in[y].push_back(i*2-1);
		out[y].push_back(i*2); in[x].push_back(i*2);
	}
	for(int i=1;i<=M*2;i++) dist[i] = 1e9;
	priority_queue<pii, vector<pii>, greater<pii>> pq;
	for(auto e : out[1]){
		dist[e] = 1;
		pq.push({1,e});
	}

	while( !pq.empty() ){
		int cur = pq.top().Se,  curd = pq.top().Fi;
		pq.pop();
		if( curd != dist[cur] ) continue;

		int x = from[cur], y = to[cur], z = c[cur];
		for(auto e : out[y]){
			int t = 1;
			if( c[e] == z ) t = 0;
			if( dist[e] > curd + t ){
				dist[e] = curd + t;
				pq.push({dist[e],e});
			}
		}
	}


	int ans = 1e9;
	for(auto e : in[N]){
		ans = min(ans, dist[e]);
	}
	if( ans >= 1e8 ) printf("-1\n");
	else printf("%d\n",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:36:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&M);
                     ^
./Main.cpp:38:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   int x,y,z; scanf("%d%d%d",&x,&y,&z);
                                      ^

Judge Result