add Patience Sort

sorting_algorithms/patience_sort.r

@@ -0,0 +1,56 @@
+# Patience Sort Function
+# Sorts an input vector using the Patience Sort algorithm.
+# Parameters:
+# - arr: Input vector to be sorted.
+# Returns:
+# - Sorted vector.
+
+patience_sort <- function(arr) {
+  if (length(arr) == 0) {
+    return(arr)
+  }
+
+  piles <- list()
+
+  # Build piles
+  for (x in arr) {
+    placed <- FALSE
+    for (i in seq_along(piles)) {
+      if (x < tail(piles[[i]], n=1)) {
+        piles[[i]] <- c(piles[[i]], x)
+        placed <- TRUE
+        break
+      }
+    }
+    if (!placed) {
+      piles[[length(piles) + 1]] <- c(x)
+    }
+  }
+
+  # Collect sorted elements
+  sorted_arr <- c()
+  while (length(piles) > 0) {
+    # Find the pile with the smallest top element
+    min_top <- Inf
+    min_index <- -1
+    for (i in seq_along(piles)) {
+      if (tail(piles[[i]], n=1) < min_top) {
+        min_top <- tail(piles[[i]], n=1)
+        min_index <- i
+      }
+    }
+    # Remove the smallest top element and add it to the sorted array
+    sorted_arr <- c(sorted_arr, min_top)
+    piles[[min_index]] <- head(piles[[min_index]], -1)
+    if (length(piles[[min_index]]) == 0) {
+      piles[[min_index]] <- NULL
+    }
+  }
+
+  return(sorted_arr)
+}
+
+# Example usage:
+elements_vec <- c(4, 3, 2, 1)
+patience_sorted_vec <- patience_sort(elements_vec)
+print(patience_sorted_vec)