Add strand sort (#136)

Author: SimonWaldherr

sorting_algorithms/strand_sort.r

@@ -0,0 +1,63 @@
+# Strand Sort Function
+# Sorts an input vector using the Strand Sort algorithm.
+# Parameters:
+# - arr: Input vector to be sorted.
+# Returns:
+# - Sorted vector.
+
+strand_sort <- function(arr) {
+  if (length(arr) <= 1) {
+    return(arr)
+  }
+  
+  output <- c()
+  
+  while (length(arr) > 0) {
+    sublist <- c(arr[1])
+    arr <- arr[-1]
+    i <- 1
+    while (i <= length(arr)) {
+      if (arr[i] >= tail(sublist, n=1)) {
+        sublist <- c(sublist, arr[i])
+        arr <- arr[-i]
+      } else {
+        i <- i + 1
+      }
+    }
+    output <- merge_sorted_lists(output, sublist)
+  }
+  
+  return(output)
+}
+
+# Helper function to merge two sorted lists
+merge_sorted_lists <- function(list1, list2) {
+  result <- c()
+  i <- 1
+  j <- 1
+  
+  while (i <= length(list1) && j <= length(list2)) {
+    if (list1[i] <= list2[j]) {
+      result <- c(result, list1[i])
+      i <- i + 1
+    } else {
+      result <- c(result, list2[j])
+      j <- j + 1
+    }
+  }
+  
+  if (i <= length(list1)) {
+    result <- c(result, list1[i:length(list1)])
+  }
+  
+  if (j <= length(list2)) {
+    result <- c(result, list2[j:length(list2)])
+  }
+  
+  return(result)
+}
+
+# Example usage:
+elements_vec <- c(4, 2, 5, 3, 1)
+strand_sorted_vec <- strand_sort(elements_vec)
+print(strand_sorted_vec)