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Task/Sorting-algorithms-Merge-sort/R/sorting-algorithms-merge-sort.r

@@ -0,0 +1,40 @@
+mergesort <- function(m)
+{
+   merge_ <- function(left, right)
+   {
+      result <- c()
+      while(length(left) > 0 && length(right) > 0)
+      {
+         if(left[1] <= right[1])
+         {
+            result <- c(result, left[1])
+            left <- left[-1]
+         } else
+         {
+            result <- c(result, right[1])
+            right <- right[-1]
+         }
+      }
+      if(length(left) > 0) result <- c(result, left)
+      if(length(right) > 0) result <- c(result, right)
+      result
+   }
+
+   len <- length(m)
+   if(len <= 1) m else
+   {
+      middle <- length(m) / 2
+      left <- m[1:floor(middle)]
+      right <- m[floor(middle+1):len]
+      left <- mergesort(left)
+      right <- mergesort(right)
+      if(left[length(left)] <= right[1])
+      {
+         c(left, right)
+      } else
+      {
+         merge_(left, right)
+      }
+   }
+}
+mergesort(c(4, 65, 2, -31, 0, 99, 83, 782, 1)) # -31   0   1   2   4  65  83  99 782