pancake_sort added

sorting_algorithms/pancake_sort.r

@@ -0,0 +1,45 @@
+# Function to flip the first 'k' elements of an array
+flip <- function(arr, k) {
+  arr[1:k] <- rev(arr[1:k])  # Reverse the first 'k' elements
+  return(arr)
+}
+
+# Function to find the index of the maximum element in an array
+findMaxIndex <- function(arr, n) {
+  maxIndex <- 1
+  for (i in 2:n) {
+    if (arr[i] > arr[maxIndex]) {
+      maxIndex <- i
+    }
+  }
+  return(maxIndex)
+}
+
+# Function to perform Pancake Sort
+pancakeSort <- function(arr) {
+  n <- length(arr)
+
+  for (currentSize in n:2) {
+    # Find the index of the maximum element in the unsorted part of the array
+    maxIndex <- findMaxIndex(arr, currentSize)
+
+    # If the maximum element is not at the end of the unsorted part, flip it
+    if (maxIndex != currentSize) {
+      # Flip the maximum element to the beginning of the array
+      arr <- flip(arr, maxIndex)
+
+      # Flip the maximum element to its correct position
+      arr <- flip(arr, currentSize)
+    }
+  }
+
+  return(arr)
+}
+
+# Example usage:
+arr <- c(3, 1, 5, 2, 4)
+cat("Original Array:", arr, "\n")
+
+# Call the Pancake Sort function to sort the array
+sortedArr <- pancakeSort(arr)
+cat("Sorted Array:", sortedArr, "\n")