From ae40ca4f4dbb86ed72cdd7ea5f23532caa5dd42e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=BB=84=E6=B5=B7?= <10402852@qq.com>
Date: Mon, 8 Jan 2024 11:21:20 +0800
Subject: [PATCH] 'commit'

---
 TangDou/AcWing/MinimalSpanningTree/859.cpp    | 11 ++--
 TangDou/AcWing/MinimalSpanningTree/859.md     | 11 ++--
 .../T3/MinialSpanningTree/1141_Kruskal.cpp    | 64 +++++++++++--------
 3 files changed, 49 insertions(+), 37 deletions(-)

diff --git a/TangDou/AcWing/MinimalSpanningTree/859.cpp b/TangDou/AcWing/MinimalSpanningTree/859.cpp
index 94467d6..e5f6057 100644
--- a/TangDou/AcWing/MinimalSpanningTree/859.cpp
+++ b/TangDou/AcWing/MinimalSpanningTree/859.cpp
@@ -24,7 +24,7 @@ int find(int x) {
 }
 
 // Kruskal算法
-int kruskal() {
+void kruskal() {
     // 1、按边权由小到大排序
     sort(edge, edge + m);
     // 2、并查集初始化
@@ -37,8 +37,7 @@ int kruskal() {
             p[a] = b, res += c, cnt++; // cnt是指已经连接上边的数量
     }
     // 4、特判是不是不连通
-    if (cnt < n - 1) return INF;
-    return res;
+    if (cnt < n - 1) res = INF;
 }
 
 int main() {
@@ -48,10 +47,10 @@ int main() {
         cin >> a >> b >> c;
         edge[i] = {a, b, c};
     }
-    int t = kruskal();
-    if (t == INF)
+    kruskal();
+    if (res == INF)
         puts("impossible");
     else
-        printf("%d\n", t);
+        printf("%d\n", res);
     return 0;
 }
\ No newline at end of file
diff --git a/TangDou/AcWing/MinimalSpanningTree/859.md b/TangDou/AcWing/MinimalSpanningTree/859.md
index 84141df..f802ad9 100644
--- a/TangDou/AcWing/MinimalSpanningTree/859.md
+++ b/TangDou/AcWing/MinimalSpanningTree/859.md
@@ -122,7 +122,7 @@ int find(int x) {
 }
 
 // Kruskal算法
-int kruskal() {
+void kruskal() {
     // 1、按边权由小到大排序
     sort(edge, edge + m);
     // 2、并查集初始化
@@ -135,8 +135,7 @@ int kruskal() {
             p[a] = b, res += c, cnt++; // cnt是指已经连接上边的数量
     }
     // 4、特判是不是不连通
-    if (cnt < n - 1) return INF;
-    return res;
+    if (cnt < n - 1) res = INF;
 }
 
 int main() {
@@ -146,11 +145,11 @@ int main() {
         cin >> a >> b >> c;
         edge[i] = {a, b, c};
     }
-    int t = kruskal();
-    if (t == INF)
+    kruskal();
+    if (res == INF)
         puts("impossible");
     else
-        printf("%d\n", t);
+        printf("%d\n", res);
     return 0;
 }
 ```
\ No newline at end of file
diff --git a/TangDou/AcWing_TiGao/T3/MinialSpanningTree/1141_Kruskal.cpp b/TangDou/AcWing_TiGao/T3/MinialSpanningTree/1141_Kruskal.cpp
index eb79e42..166a5e8 100644
--- a/TangDou/AcWing_TiGao/T3/MinialSpanningTree/1141_Kruskal.cpp
+++ b/TangDou/AcWing_TiGao/T3/MinialSpanningTree/1141_Kruskal.cpp
@@ -1,44 +1,58 @@
 #include <bits/stdc++.h>
 using namespace std;
 const int N = 110, M = 210;
-int n, m, fa[N];
+const int INF = 0x3f3f3f3f;
 
-//结构体
-struct Edge {
-    int a, b, w;
-    bool operator<(const Edge &t) {
-        return w < t.w;
+int n, m; // n条顶点,m条边
+int res;  // 最小生成树的权值和
+int cnt;  // 最小生成树的结点数
+
+// Kruskal用到的结构体
+struct Node {
+    int a, b, c;
+    bool const operator<(const Node &t) const {
+        return c < t.c; // 边权小的在前
     }
-} e[M];
+} edge[M]; // 数组长度为是边数
 
-//并查集
+// 并查集
+int p[N];
 int find(int x) {
-    if (fa[x] != x) fa[x] = find(fa[x]); //路径压缩
-    return fa[x];
+    if (p[x] != x) p[x] = find(p[x]);
+    return p[x];
+}
+
+// Kruskal算法
+int kruskal() {
+    // 1、按边权由小到大排序
+    sort(edge, edge + m);
+    // 2、并查集初始化
+    for (int i = 1; i <= n; i++) p[i] = i;
+    // 3、迭代m次
+    for (int i = 0; i < m; i++) {
+        int a = edge[i].a, b = edge[i].b, c = edge[i].c;
+        a = find(a), b = find(b);
+        if (a != b)
+            p[a] = b, res += c, cnt++; // cnt是指已经连接上边的数量
+    }
+    // 4、特判是不是不连通
+    if (cnt < n - 1) return INF;
+    return res;
 }
+
 int main() {
     cin >> n >> m;
 
-    //并查集初始化
-    for (int i = 1; i <= n; i++) fa[i] = i;
-
+    int sum = 0;
     // Kruskal算法直接记录结构体
     for (int i = 0; i < m; i++) {
         int a, b, c;
         cin >> a >> b >> c;
-        e[i] = {a, b, c};
+        edge[i] = {a, b, c};
+        sum += c;
     }
-    sort(e, e + m); //不要忘记e数组的长度是边的数量
 
-    int res = 0;
-    //枚举每条边
-    for (int i = 0; i < m; i++) {
-        int a = find(e[i].a), b = find(e[i].b), c = e[i].w;
-        if (a != b)
-            fa[a] = b;
-        else
-            res += c; //去掉的边权
-    }
-    printf("%d\n", res);
+    int t = kruskal();
+    printf("%d\n", sum - t);
     return 0;
 }