HDU 6005 Pandaland——dijkstra + 剪枝

HDU 6005 Pandaland——dijkstra + 剪枝

#include #include #include #include #include #include #include

G[maxn];map m;void init() { cnt = 0; ans = INF; for (int i = 0; i < maxn; i++) { G[i].clear(); } m.clear();}void dijkstra(int s, int e, int x) { for (int i = 0; i < maxn; i++) { d[i] = INF; vis[i] = 0; } d[s] = 0; priority_queue, greater

> q; q.push(make_pair(0, s)); while (!q.empty()) { P p = q.top(); q.pop(); int u = p.second, dis = p.first; if (dis + x >= ans) break; if (vis[u]) continue; vis[u] = 1; for (int i = 0; i < G[u].size(); i++) { int v = G[u][i].first, id = G[u][i].second; int cost = edge[id].cost; if (d[v] > d[u] + cost) { d[v] = d[u] + cost; q.push(make_pair(d[v], v)); } } } ans = min(ans, d[e] + x);}int main() { scanf("%d", &T); for (int kase = 1; kase <= T; kase++) { scanf("%d", &n); init(); for (int i = 1; i <= n; i++) { int x1, y1, x2, y2, w; scanf("%d %d %d %d %d", &x1, &y1, &x2, &y2, &w); P p1 = make_pair(x1, y1), p2 = make_pair(x2, y2); if (!m[p1]) m[p1] = ++cnt; if (!m[p2]) m[p2] = ++cnt; int u = m[p1], v = m[p2]; G[u].push_back(make_pair(v, i)); G[v].push_back(make_pair(u, i)); edge[i].u = u, edge[i].v = v, edge[i].cost = w; } for (int i = 1; i <= n; i++) { int u = edge[i].u, v = edge[i].v, cost = edge[i].cost; edge[i].cost = INF; dijkstra(u, v, cost); edge[i].cost = cost; } if (ans == INF) ans = 0; printf("Case #%d: %d\n", kase, ans); } return 0;}

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