P1529 [USACO2.4]回家 Bessie Come Home

R54898868

Luogu/problem/P1529/P1529.cpp

@@ -0,0 +1,56 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int p, w, dist[105];
+char u, v;
+bool vis[105];
+vector<pair<int, int>> g[105];
+pair<int, char> ans;
+map<char, int> keymap;
+map<int, char> rekeymap;
+
+void dijkstra() {
+    memset(dist, 0x3f, sizeof(dist));
+    memset(vis, 0x00, sizeof(vis));
+    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
+    dist[keymap['Z']] = 0;
+    q.push(make_pair(0, keymap['Z']));
+    while (!q.empty()) {
+        auto t = q.top();
+        q.pop();
+        if (vis[t.second]) continue;
+        for (auto i : g[t.second]) {
+            if (dist[i.first] > t.first + i.second) {
+                dist[i.first] = t.first + i.second;
+                q.push(make_pair(dist[i.first], i.first));
+            }
+        }
+        vis[t.second] = true;
+    }
+}
+
+int main() {
+    cin >> p;
+    for (int i = 1; i <= 26; i++) {
+        keymap[i - 1 + 'a'] = i;
+        rekeymap[i] = i - 1 + 'a';
+        keymap[i - 1 + 'A'] = i + 26;
+        rekeymap[i + 26] = i - 1 + 'A';
+    }
+    for (int i = 1; i <= p; i++) {
+        cin >> u >> v >> w;
+        g[keymap[u]].push_back(make_pair(keymap[v], w));
+        g[keymap[v]].push_back(make_pair(keymap[u], w));
+    }
+    dijkstra();
+    ans = make_pair(0x3f3f3f3f, 0);
+    for (int i = keymap['A']; i < keymap['Z']; i++) {
+        if (ans.first > dist[i]) {
+            ans.first = dist[i];
+            ans.second = rekeymap[i];
+        }
+    }
+    cout << ans.second << ' ' << ans.first << endl;
+    return 0;
+}