POJ 2387 Til the Cows Come Home

题目大意：

题目链接

注释代码：

无注释代码：

#include <iostream>#include <cstdio>#include <queue>#defineINF1000000#defineMAXN1000#defineMAXM4000using namespace std;structArc {intv;intc;Arc(void) {}Arc(int vv, int cc) : v(vv), c(cc) {}};structNode {intu;intd;Node(void) {}Node(int uu, int dd) : u(uu), d(dd) {}booloperator<(const Node &oth)const {return d > oth.d;}};Arcarc[MAXM + 1];inthead[MAXN + 1];intnxt[MAXM + 1];inte;intdis[MAXN + 1];boolvis[MAXN + 1];priority_queue<Node>heap;voidaddarc( int u, int v, int c ) {arc[e].v = v;arc[e].c = c;nxt[e]  = head[u];head[u] = e++;}intdij(int n) {intu, v;inti;Nodenode;for ( i = 1; i <= n; i++ ) dis[i] = INF;heap.push(Node(1, 0));dis[1] = 0;while (true) {node = heap.top();heap.pop();if ( ( u = node.u ) == n ) return dis[n];if ( vis[u] ) continue;vis[u] = true;for ( i = head[u]; i; i = nxt[i] )if ( !vis[ v = arc[i].v ] && dis[u] + arc[i].c < dis[v] ) {dis[v] = dis[u] + arc[i].c;heap.push(Node(v, dis[v]));}}return -1;}intmain() {intn, m;intu, v, c;e = 1;scanf("%d%d", &m, &n);while ( m-- ) {scanf("%d%d%d", &u, &v, &c);addarc( u, v, c );addarc( v, u, c );}printf("%d\n", dij(n));return 0;}