From 63c516cbb46c090219fd9f058f3eff059fde30a8 Mon Sep 17 00:00:00 2001
From: alvredaivena <alvredaivena@yahoo.co.id>
Date: Sun, 14 Dec 2014 06:19:54 +0700
Subject: [PATCH] added Dijkstra

---
 Dijkstra.go | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 README.md   |  3 ++-
 2 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100644 Dijkstra.go

diff --git a/Dijkstra.go b/Dijkstra.go
new file mode 100644
index 0000000..6e2a361
--- /dev/null
+++ b/Dijkstra.go
@@ -0,0 +1,70 @@
+package main
+
+import "fmt"
+import "sort"
+
+// O(n)
+func MinCost(cost []int, dist []int) (int, int) {
+	minn := 100000000
+	to := 100000000
+	for j:=0; j<len(cost); j++ {
+		if cost[j] != 0 && dist[j] != 1 {
+			if cost[j] < minn {
+				minn = cost[j]
+				to = j
+			} 
+		}
+	}
+	return minn, to
+}
+
+// O(n^2)
+func Dijkstra(graph [][]int, vertex int) (map[string]int, int) {
+	min := 0
+	path := make(map[string]int)
+	count := 0
+	next := 0
+	path_temp := ""
+	dist := make([]int, vertex)
+	for len(path) < vertex-1 {
+		dist[next] = 1
+		a, b := MinCost(graph[next], dist) 
+		path_temp = string(count+'1')+". "+string(next+'A')+"->"+string(b+'A')
+		path[path_temp] = a
+		min += a
+		next = b
+		count += 1
+	}
+	return path, min
+}
+
+func main(){
+	vertex := 5
+	/*
+	      2    3
+       A----B----C
+       |   / \   |
+      6| 8/   \5 |7
+       | /     \ |
+	   D---------E
+            9        
+	*/
+	graph := [][]int{
+					{0, 2, 0, 6, 0},
+                    {2, 0, 3, 8, 5},
+                    {0, 3, 0, 0, 7},
+                    {6, 8, 0, 0, 9},
+                    {0, 5, 7, 9, 0},
+			}
+	path, min := Dijkstra(graph, vertex)
+	fmt.Println("Shortest path : ")
+	var keys []string
+    for k := range path {
+        keys = append(keys, k)
+    }
+    sort.Strings(keys)
+	for _, k := range keys {
+        fmt.Println(k, ":", path[k])
+    }
+	fmt.Println("Total cost :", min)
+}
diff --git a/README.md b/README.md
index e996964..a2c39ba 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ ChangeLog:
 * 2014-12-11 added QuickSort, CombSort, Heapsort (Agung)
 * 2014-12-11 added CocktailSort, added Non-recursive MergeSort (Alvreda)
 * 2014-12-13 added Shellsort( versi biasa, Ciura, Knuth) (Marcelinus Devin)
+* 2014-12-14 added Dijkstra (Alvreda)
 
 TODO:
 =====
@@ -44,4 +45,4 @@ BOUNTY:
 * implement Non-recursive Inplace MergeSort +1800, other sorting algorithms, that allow Less/Equal/Swap/Len interface
 * implement BinarySearch, JumpSearch, InterpolationSearch +400 that Allow Less/Equal interface
 * implement R-Tree +5000, k-d Tree +8000 (using reflection)
-* implement any other data structure or algorithm (bounty may vary, contact me for details)
\ No newline at end of file
+* implement any other data structure or algorithm (bounty may vary, contact me for details)