From 093d0e9812fe78f8ae2c985d85e8c6679fa896a8 Mon Sep 17 00:00:00 2001
From: tonyhawkcxx <tonyhawkcxx@noreply.localhost>
Date: Tue, 26 Mar 2024 16:53:46 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=8A=E4=BC=A0=E6=96=87=E4=BB=B6=E8=87=B3?=
 =?UTF-8?q?=20/?=
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---
 floyd.cpp | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 floyd.cpp

diff --git a/floyd.cpp b/floyd.cpp
new file mode 100644
index 0000000..013a42c
--- /dev/null
+++ b/floyd.cpp
@@ -0,0 +1,46 @@
+class Graph {
+public:
+    vector<vector<int>> dist;
+    int num;
+    Graph(int n, vector<vector<int>>& edges) {
+        num=n;
+        dist=vector<vector<int>>(n,vector<int>(n,INT_MAX));//所有端点之间距离初始化为无穷大
+        for (int i=0;i<n;i++) dist[i][i]=0;//自己到自己的距离为0
+        int m=edges.size();
+        for (int i=0;i<m;i++){
+            dist[edges[i][0]][edges[i][1]]=edges[i][2]; //添加一条边，左端点到右端点的距离为cost
+        }
+        for (int k=0;k<n;k++){ //对于每一个端点，看它是否可以作为中间点连接另外两个端点a和b，如果比直接连接ab更近，则更新ab之间的最短距离
+            for (int i=0;i<n;i++){
+                for (int j=0;j<n;j++){
+                    if (dist[i][k] != INT_MAX && dist[k][j] != INT_MAX){
+                        dist[i][j] = min (dist[i][j], dist[i][k]+dist[k][j]);
+                    }
+                }
+            }
+        }
+    }
+    
+    void addEdge(vector<int> edge) {
+        if (edge[2]>dist[edge[0]][edge[1]]) //如果添加的边的权值大于已有最短路径权值，不需要更新dist[][]，直接返回
+            return;
+        for (int i=0;i<num;i++){ //对于每一对端点ij，看是否可以通过edge作为中间边连接，比直接连接ij更近，则更新ij之间的最短距离
+            for (int j=0;j<num;j++){
+                if (dist[i][edge[0]] != INT_MAX && dist[edge[1]][j] != INT_MAX){
+                    dist[i][j] = min (dist[i][j], dist[i][edge[0]]+dist[edge[1]][j]+edge[2]);
+                }
+            }
+        }
+    }
+    
+    int shortestPath(int node1, int node2) {
+        return dist[node1][node2]==INT_MAX?-1:dist[node1][node2];
+    }
+};
+
+/**
+ * Your Graph object will be instantiated and called as such:
+ * Graph* obj = new Graph(n, edges);
+ * obj->addEdge(edge);
+ * int param_2 = obj->shortestPath(node1,node2);
+ */