20250925 baekjoon

code_study/Baekjoon/swift/1504.swift

@@ -0,0 +1,83 @@
+let inf: Int = 987654321
+
+func dijk(from start: Int,_ node: [[(Int,Int)]], _ n: Int) -> [Int] {
+    var dist: [Int] = Array(repeating: inf, count: n+1)
+    dist[start] = 0
+    var qu = [(Int, Int)]()
+    qu.append((start, 0))
+    
+    while !qu.isEmpty {
+        if let (now, weight) = qu.first {
+            qu.removeFirst()
+            
+            if dist[now] < weight {
+                continue
+            }
+            
+            for tup in node[now] {
+                if dist[tup.0] > tup.1 + weight {
+                    dist[tup.0] = tup.1 + weight
+                    qu.append((tup.0, dist[tup.0]))
+                }
+            }
+        }
+    }
+    
+    return dist
+}
+
+if let input1 = readLine(),
+   let temp1 = input1.split(separator: " ").compactMap({Int($0)}) as? [Int],
+   let N: Int = temp1.first, let E: Int = temp1.last
+{
+    var node: [[(Int, Int)]] = Array(repeating: [(Int, Int)](), count: N+1)
+    
+    for _ in 0..<E {
+        if let input2 = readLine(),
+           let temp2 = input2.split(separator: " ").compactMap({Int($0)}) as? [Int],
+           temp2.count == 3
+        {
+            let u: Int = temp2[0]
+            let v: Int = temp2[1]
+            let c: Int = temp2[2]
+            
+            node[u].append((v,c))
+            node[v].append((u,c))
+        }
+    }
+    
+    if let input3 = readLine(),
+       let temp3 = input3.split(separator: " ").compactMap({Int($0)}) as? [Int],
+       let v1: Int = temp3.first, let v2: Int = temp3.last
+    {
+        let Dist_from1: [Int] = dijk(from: 1, node, N)
+        let Dist_fromV1: [Int] = dijk(from: v1, node, N)
+        let Dist_fromV2: [Int] = dijk(from: v2, node, N)
+        
+        print(Dist_from1)
+        print(Dist_fromV1)
+        print(Dist_fromV2)
+        
+        //path1 1->v1->v2->N
+        var path1: Int = -1
+        if Dist_from1[v1] < inf && Dist_fromV1[v2] < inf && Dist_fromV2[N] < inf {
+            path1 = Dist_from1[v1] + Dist_fromV1[v2] + Dist_fromV2[N]
+        }
+        
+        //path2 1->v2->v1->N
+        var path2: Int = -1
+        if Dist_from1[v2] < inf && Dist_fromV2[v1] < inf && Dist_fromV1[N] < inf {
+            path2 = Dist_from1[v2] + Dist_fromV2[v1] + Dist_fromV1[N]
+        }
+        
+        if path1 == -1 && path2 == -1 {
+            print(-1)
+        }
+        else if path1 == -1 || path2 == -1 {
+            print(max(path1, path2))
+        }
+        else {
+            print(min(path1, path2))
+        }
+    }
+}