From b39982830099c5235d6c7f2a7cd1363d82d96ec5 Mon Sep 17 00:00:00 2001
From: Ren Baoshuo <i@baoshuo.ren>
Date: Tue, 10 Aug 2021 10:53:07 +0800
Subject: [PATCH] =?UTF-8?q?858.=20Prim=E7=AE=97=E6=B3=95=E6=B1=82=E6=9C=80?=
 =?UTF-8?q?=E5=B0=8F=E7=94=9F=E6=88=90=E6=A0=91?=
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https://www.acwing.com/problem/content/submission/code_detail/7021576/
---
 AcWing/858/858.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 AcWing/858/858.cpp

diff --git a/AcWing/858/858.cpp b/AcWing/858/858.cpp
new file mode 100644
index 00000000..7c46a196
--- /dev/null
+++ b/AcWing/858/858.cpp
@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, m, u, v, w, g[505][505], dist[505];
+bool vis[505];
+
+int prim() {
+    memset(dist, 0x3f, sizeof(dist));
+    int res = 0;
+    for (int i = 0; i < n; i++) {
+        int t = -1;
+        for (int j = 1; j <= n; j++) {
+            if (!vis[j] && (t == -1 || dist[j] < dist[t])) {
+                t = j;
+            }
+        }
+        if (i && dist[t] == 0x3f3f3f3f) return 0x3f3f3f3f;
+        if (i) res += dist[t];
+        for (int j = 1; j <= n; j++) {
+            dist[j] = min(dist[j], g[t][j]);
+        }
+        vis[t] = true;
+    }
+    return res;
+}
+
+int main() {
+    cin >> n >> m;
+    memset(g, 0x3f, sizeof(g));
+    for (int i = 0; i < m; i++) {
+        cin >> u >> v >> w;
+        g[u][v] = g[v][u] = min(g[u][v], w);
+    }
+    int ans = prim();
+    if (ans == 0x3f3f3f3f) {
+        cout << "impossible" << endl;
+    } else {
+        cout << ans << endl;
+    }
+    return 0;
+}