POJ 3159 Candies

题目大意：

题目链接

注释代码：

无注释代码：

#include <iostream>
#include <cstdio>
#include <queue>
#include <vector>

#define	INF		1000000000

#define	MAXN	30000
#define	MAXM	150000

using namespace std;

struct	Arc {

	int		v;
	int		c;

	Arc(void) {}
	Arc(int vv, int cc) : v(vv), c(cc) {}
};

struct	Node {

	int		u;
	int		d;

	Node(void) {}
	Node(int uu, int dd) : u(uu), d(dd) {}

	bool
	operator<(const Node &oth)
	const {
	
		return d > oth.d;
	}
};

Arc		arc[MAXM + 1];
int		nxt[MAXM + 1];
int		head[MAXN + 1];
int		e;

int		d[MAXN + 1];
bool	vis[MAXN + 1];

priority_queue<Node>	heap;

void
addarc( int u, int v, int c ) {

	arc[e].v = v;
	arc[e].c = c;

	nxt[e]	= head[u];
	head[u] = e++;
}

int
dij(int n) {

	int		i;
	int		u, v;

	Node	node;

	for ( i = 1; i <= n; i++ ) d[i] = INF;

	d[1]   = 0;
	heap.push(Node(1, 0));
	while ( !heap.empty() ) {
	
		node = heap.top();
		heap.pop();

		if ( ( u = node.u ) == n ) return d[n];
		if ( vis[u] ) continue;

		vis[u] = true;
		for ( i = head[u]; i; i = nxt[i] )
			if ( !vis[ v = arc[i].v ] && d[u] + arc[i].c < d[v] ) {
			
				d[v] = d[u] + arc[i].c;
				heap.push(Node(v, d[v]));
			}
	}

	return d[n];
}

int
main() {

	int		n, m;
	int		u, v, c;

	e = 1;
	scanf("%d%d", &n, &m);
	while ( m-- ) {

		scanf("%d%d%d", &u, &v, &c);
		addarc( u, v, c );
	}
	printf("%d\n", dij(n));

	return 0;
}