add numerical recipes library

lib/nr/k_and_r/recipes/reverse.c

@@ -0,0 +1,15 @@
+
+void reverse(iorder,ncity,n)
+int iorder[],n[],ncity;
+{
+	int nn,j,k,l,itmp;
+
+	nn=(1+((n[2]-n[1]+ncity) % ncity))/2;
+	for (j=1;j<=nn;j++) {
+		k=1 + ((n[1]+j-2) % ncity);
+		l=1 + ((n[2]-j+ncity) % ncity);
+		itmp=iorder[k];
+		iorder[k]=iorder[l];
+		iorder[l]=itmp;
+	}
+}