Add Maximum Array Rotation in Awk

archive/a/awk/maximum-array-rotation.awk

@@ -0,0 +1,57 @@
+function usage() {
+    print "Usage: please provide a list of integers (e.g. \"8, 3, 1, 2\")"
+    exit(1)
+}
+
+function str_to_number(s) {
+    return (s ~ /^\s*[+-]*[0-9]+\s*$/) ? s + 0 : "ERROR"
+}
+
+function str_to_array(s, arr,  str_arr, idx, result) {
+    split(s, str_arr, ",")
+    for (idx in str_arr) {
+        result = str_to_number(str_arr[idx])
+        if (result == "ERROR") {
+            delete arr
+            arr[1] = "ERROR"
+            break
+        } else {
+            arr[idx] = result
+        }
+    }
+}
+
+function maximum_array_rotation(arr, n,  i, s, w, wmax) {
+    # Calculate sum and initial array rotation
+    for (i = 1; i <= n; i++) {
+        s += arr[i]
+        w += (i - 1) * arr[i]
+    }
+
+    # Initialize maximum array rotation
+    wmax = w
+
+    # Adjust array rotation and update maximum
+    for (i = 1; i < n; i++) {
+        w += n * arr[i] - s
+        if (w > wmax) {
+            wmax = w
+        }
+    }
+    return wmax
+}
+
+BEGIN {
+    if (ARGC < 2) {
+        usage()
+    }
+
+    str_to_array(ARGV[1], arr)
+    arr_len = length(arr)
+    if (!arr_len || arr[1] == "ERROR") {
+        usage()
+    }
+
+    result = maximum_array_rotation(arr, arr_len)
+    printf("%d\n", result)
+}