day 1 cannot mawk but it can gawk

d01/run.awk

@@ -0,0 +1,16 @@
+{
+    l[NR] = $1
+    r[NR] = $2
+    C[$2]++
+}
+
+END {
+    asort(l)
+    asort(r)
+    for (i = 1; i <= NR; i++) {
+        d = l[i] - r[i]
+        D1 += (d < 0) ? -d : d
+        D2 += l[i] * C[l[i]]
+    }
+    print D1, D2
+}