day 6, AWK solution

d06/exec.awk

@@ -0,0 +1,19 @@
+BEGIN {W=14}
+{
+	for (i=1; i<=length($1); i++) {
+		window = substr($1,i,W)
+		S=0
+		# compare each char of window to all char of window
+		for (j=1; j<=W; j++) {
+			for (k=1; k<=W; k++) {
+				if (substr(window,j,1) == substr(window,k,1)) {
+					S+=1
+				}
+			}
+		}
+		if (S == W) {
+			print "fin : " i + W - 1
+			next
+		}
+	}
+}