Submission #880117

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Source Code Expand

#include <iostream>
#include <cstdio>
#include <vector>
#include <set>
#include <map>
using namespace std;

const int inf = 17070509, maxN = int(1e5)+5;

int n, m;
int res[maxN+10];
map<int, int> D[maxN+10];
vector<pair<int, int>> graph[maxN+10];

int dijkstra(int node)
{
	set<pair<int, pair<int, int>>> Q;

	for(auto it: graph[node]) Q.insert({1, {node, it.second}});

	pair<int, pair<int, int>> top;
	while(!Q.empty())
	{
		top = *Q.begin();
		Q.erase(Q.begin());

		for(auto it: graph[top.second.first])
		{
			if(D[it.first].find(it.second) == D[it.first].end())
			{
				D[it.first][it.second] = top.first+(top.second.second!=it.second);
				Q.insert({top.first+(top.second.second!=it.second), it});
				res[it.first] = min(res[it.first], top.first+(top.second.second!=it.second));
			}
			else if(D[it.first][it.second] > top.first+(top.second.second!=it.second))
			{
				Q.erase({D[it.first][it.second], it});
				D[it.first][it.second] = top.first+(top.second.second!=it.second);
				Q.insert({top.first+(top.second.second!=it.second), it});
				res[it.first] = min(res[it.first], top.first+(top.second.second!=it.second));
			}
		}
	}
	return res[n-1];
}

int main(void)
{
	int u, v, c;
	scanf("%d%d", &n, &m);
	for(int i = 0;i < n;i++) res[i] = inf;
	for(int i = 0;i < m;i++)
	{
		scanf("%d%d%d", &u, &v, &c);
		u--; v--;
		graph[u].push_back({v, c});
		graph[v].push_back({u, c});
	}

	int res = dijkstra(0);
	if(res == inf) printf("-1\n");
	else printf("%d\n", res);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:50:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
                       ^
./Main.cpp:54:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d", &u, &v, &c);
                              ^

Judge Result