new file: P8074.cpp

2026-08-12 23:05:17 +08:00
parent 4875c2aa39
commit 04bfa3ab91
1 changed files with 83 additions and 0 deletions
@@ -0,0 +1,83 @@
+#include <bits/stdc++.h>
+#define int long long
+using namespace std;
+int n;
+struct node
+{
+    int x, y, z, id;
+} star[100005];
+bool cmpx(node a, node b)
+{
+    return a.x < b.x;
+}
+bool cmpy(node a, node b)
+{
+    return a.y < b.y;
+}
+bool cmpz(node a, node b)
+{
+    return a.z < b.z;
+}
+struct edge
+{
+    int u, v, w;
+    const bool operator<(const edge b) const
+    {
+        return w < b.w;
+    }
+} gra[500005];
+int tot;
+int fa[100005];
+int find(int now)
+{
+    if (fa[now] == now)
+        return now;
+    return fa[now] = find(fa[now]);
+}
+signed main()
+{
+    scanf("%lld", &n);
+    for (int i = 1; i <= n; ++i)
+    {
+        scanf("%lld%lld%lld", &star[i].x, &star[i].y, &star[i].z);
+        fa[i] = i;
+        star[i].id = i;
+    }
+    sort(star + 1, star + n + 1, cmpx);
+    for (int i = 1; i < n; ++i)
+    {
+        gra[tot].u = star[i].id;
+        gra[tot].v = star[i + 1].id;
+        gra[tot++].w = abs(star[i].x - star[i + 1].x);
+    }
+    sort(star + 1, star + n + 1, cmpy);
+    for (int i = 1; i < n; ++i)
+    {
+        gra[tot].u = star[i].id;
+        gra[tot].v = star[i + 1].id;
+        gra[tot++].w = abs(star[i].y - star[i + 1].y);
+    }
+    sort(star + 1, star + n + 1, cmpz);
+    for (int i = 1; i < n; ++i)
+    {
+        gra[tot].u = star[i].id;
+        gra[tot].v = star[i + 1].id;
+        gra[tot++].w = abs(star[i].z - star[i + 1].z);
+    }
+    sort(gra, gra + tot);
+    int cnt = 0, num = 0;
+    for (int i = 0; i < tot && cnt < n - 1; ++i)
+    {
+        int fu = find(gra[i].u);
+        int fv = find(gra[i].v);
+
+        if (fu != fv)
+        {
+            fa[fu] = fv; // 必须合并根节点
+            ++cnt;
+            num += gra[i].w;
+        }
+    }
+    printf("%lld\n", num);
+    return 0;
+}