Add Zeckendorf in Awk (#5327)

Author: rzuckerm

archive/a/awk/zeckendorf.awk

@@ -0,0 +1,61 @@
+function usage() {
+    print "Usage: please input a non-negative integer"
+    exit(1)
+}
+
+function str_to_number(s) {
+    return (s ~ /^\s*[+-]*[0-9]+\s*$/) ? s + 0 : "ERROR"
+}
+
+function fibonacci_up_to(n, fibs,  a, b, c, k) {
+    a = 1
+    b = 2
+    for (k = 1; a <= n; k++) {
+        fibs[k] = a
+        c = a + b
+        a = b
+        b = c
+    }
+}
+
+function zeckendorf(n, zecks,  i, k) {
+    fibonacci_up_to(n, fibs)
+    k = length(fibs)
+    i = 1
+    while (k > 0 && n > 0) {
+        fib = fibs[k]
+        if (fib <= n) {
+            zecks[i++] = fib
+            n -= fib
+            k -= 2
+        } else {
+            k--
+        }
+    }
+}
+
+function show_array(arr,  idx, s) {
+    s = ""
+    for (idx in arr) {
+        if (s) {
+            s = s ", "
+        }
+        s = s arr[idx]
+    }
+
+    print s
+}
+
+BEGIN {
+    if (ARGC < 2) {
+        usage()
+    }
+
+    n = str_to_number(ARGV[1])
+    if (n == "ERROR" || n < 0) {
+        usage()
+    }
+
+    zeckendorf(n, zecks)
+    show_array(zecks)
+}