Data update

Task/Quickselect-algorithm/R/quickselect-algorithm.r

@@ -0,0 +1,21 @@
+quickselect <- function(vec, k) {
+  stopifnot(k > 0, k <= length(vec))
+  repeat {
+    pivot_index <- sample.int(length(vec), 1)
+    pivot_value <- vec[[pivot_index]]
+    left <- vec[vec < pivot_value]
+    right <- vec[vec > pivot_value]
+    pivot_index <- length(left) + 1
+    if (k == pivot_index) {
+      return(pivot_value)
+    } else if (k < pivot_index) {
+      vec <- left
+    } else {
+      k <- k - pivot_index
+      vec <- right
+    }
+  }
+}
+
+vec <- c(9, 8, 7, 6, 5, 0, 1, 2, 3, 4)
+print(sapply(1:10, quickselect, vec = vec))