From e843a971292dfc5c5355c051ae526a8ae350a21e Mon Sep 17 00:00:00 2001 From: Baoshuo Date: Sun, 15 May 2022 15:18:51 +0800 Subject: [PATCH] P2939 [USACO09FEB]Revamping Trails G https://www.luogu.com.cn/record/75807146 --- Luogu/P2939/P2939.cpp | 74 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 Luogu/P2939/P2939.cpp diff --git a/Luogu/P2939/P2939.cpp b/Luogu/P2939/P2939.cpp new file mode 100644 index 00000000..f318a0ea --- /dev/null +++ b/Luogu/P2939/P2939.cpp @@ -0,0 +1,74 @@ +#include +#include +#include +#include + +using std::cin; +using std::cout; +const char endl = '\n'; + +const int N = 1e4 + 5; + +int n, m, k, dist[N << 5]; +std::vector> g[N << 5]; +bool vis[N << 5]; + +void dijkstra() { + memset(dist, 0x3f, sizeof(dist)); + + std::priority_queue, std::vector>, std::greater>> q; + + q.push(std::make_pair(0, 1)); + dist[1] = 0; + + while (!q.empty()) { + auto t = q.top(); + q.pop(); + + if (vis[t.second]) continue; + + for (auto e : g[t.second]) { + int v = e.first, + w = e.second; + + if (dist[v] > t.first + w) { + dist[v] = t.first + w; + + q.push(std::make_pair(dist[v], v)); + } + } + + vis[t.second] = true; + } +} + +int main() { + std::ios::sync_with_stdio(false); + + cin >> n >> m >> k; + + for (int i = 1, u, v, w; i <= m; i++) { + cin >> u >> v >> w; + + g[u].push_back(std::make_pair(v, w)); + g[v].push_back(std::make_pair(u, w)); + + for (int j = 1; j <= k; j++) { + g[u + (j - 1) * n].push_back(std::make_pair(v + j * n, 0)); + g[v + (j - 1) * n].push_back(std::make_pair(u + j * n, 0)); + + g[u + j * n].push_back(std::make_pair(v + j * n, w)); + g[v + j * n].push_back(std::make_pair(u + j * n, w)); + } + } + + for (int i = 0; i <= k; i++) { + g[i * n].push_back(std::make_pair(i * n + n, 0)); + } + + dijkstra(); + + cout << dist[n * k + n] << endl; + + return 0; +}