update

poj/3259.wormholes/main.cc

@@ -0,0 +1,62 @@
+#include <cstdio>
+#include <cstring>
+
+using namespace std;
+
+const int N = 500;
+const int M = 2500;
+const int W = 200;
+const int INF = 0x3F3F3F3F;
+
+int dist[N + 1];
+
+struct E {
+  int s;
+  int e;
+  int t;
+  E(int s = 0, int e = 0, int t = 0) : s(s), e(e), t(t) {}
+} edge[2 * M + W];
+
+int main() {
+  int f, n, m, w, s, e, t, k;
+  scanf("%d", &f);
+  while (f--) {
+    scanf("%d %d %d", &n, &m, &w);
+    k = 0;
+    for (int i = 0; i < m; i++) {
+      scanf("%d %d %d", &s, &e, &t);
+      edge[k].s = s;
+      edge[k].e = e;
+      edge[k++].t = t;
+      edge[k].s = e;
+      edge[k].e = s;
+      edge[k++].t = t;
+    }
+    for (int i = 0; i < w; i++) {
+      scanf("%d %d %d", &s, &e, &t);
+      edge[k].s = s;
+      edge[k].e = e;
+      edge[k++].t = -t;
+    }
+    memset(dist, 0x3F, sizeof(dist));
+    dist[1] = 0;
+    for (int i = 1; i < n; i++) {  // Passes no more than i edges
+      for (int j = 0; j < k; j++) {
+        s = edge[j].s;
+        e = edge[j].e;
+        if (edge[j].t + dist[s] < dist[e]) dist[e] = edge[j].t + dist[s];
+      }
+    }
+    int i;
+    for (i = 0; i < k; i++) {
+      s = edge[i].s;
+      e = edge[i].e;
+      if (edge[i].t + dist[s] < dist[e]) break;
+    }
+    if (i < k)
+      printf("YES\n");
+    else
+      printf("NO\n");
+  }
+  return 0;
+}