update

poj/3159.candies/main.cc

@@ -0,0 +1,45 @@
+#include <cstdio>
+#include <cstring>
+#include <queue>
+#include <vector>
+
+using namespace std;
+
+const int N = 30000;
+const int M = 150000;
+const int INF = 0x3F3F3F3F;
+
+int dist[N + 1];
+
+struct E {
+  int v;
+  int c;
+  E(int v, int c) : v(v), c(c) {}
+  bool operator<(const E &that) const { return this->c > that.c; }
+};
+
+int main() {
+  int n, m, a, b, c, t;
+  scanf("%d %d", &n, &m);
+  memset(dist, 0x3F, sizeof(dist));
+  vector<vector<E>> adj(n + 1);
+  for (int i = 0; i < m; i++) {
+    scanf("%d %d %d", &a, &b, &c);
+    adj[a].push_back(E(b, c));
+  }
+  priority_queue<E> pq;
+  dist[1] = 0, t = 1;
+  for (int i = 0; i < adj[1].size(); i++) pq.push(adj[1][i]);
+  while (t < n) {
+    E e = pq.top();
+    pq.pop();
+    if (dist[e.v] <= e.c) continue;
+    dist[e.v] = e.c;
+    vector<E>::iterator it;
+    for (it = adj[e.v].begin(); it != adj[e.v].end(); ++it)
+      if (dist[it->v] == INF) pq.push(E(it->v, e.c + it->c));
+    t++;
+  }
+  printf("%d\n", dist[n]);
+  return 0;
+}