HDU 1863 简单最短树

#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 10000;
const int INF = 0x3f3f3f3f;
int cost[MAX_N][MAX_N];
int d[MAX_N];
bool used[MAX_N];
int M, V, a, b, c;
int dijkatra()
{
	fill(d, d + V, INF);
	fill(used, used + V, false);
	d[0] = 0;
	int res = 0;
	while (true)
	{
		int v = -1;
		for (int u = 0; u < V; u++)
			if (!used[u] && (v == -1 || d[u] < d[v]))
				v = u;
		if (v == -1)break;
		used[v] = true;
		res = (d[v] == INF || res == -1 ? -1 : res + d[v]);
		for (int u = 0; u < V; u++)
			d[u] = min(d[u], cost[v][u]);
	}
	return res;
}
int main(int argc, char const *argv[])
{
	std::ios::sync_with_stdio(false);
	while (cin >> M >> V && M)
	{
		for (int i = 0; i < V; i++)
			for (int j = 0; j < V; j++)
				cost[i][j] = INF;
		while (M--)
		{
			cin >> a >> b >> c;
			cost[a - 1][b - 1] = cost[b - 1][a - 1] = c;
		}
		int ans = dijkatra();
		if (ans == -1)cout << '?' << endl;
		else cout << ans << endl;
	}
	return 0;
}

出错输出63 蒙了原来？的ascII码值是63用三目运算符不是那么智能啊