public static void main(String[] args) throws IOException {
IO io = new IO(System.in);
int sum;
while (true) {
int nV = io.nextInt();
int nE = io.nextInt();
if (nV == 0) {
break;
}
V[] vertices = new V[nV];
E[] edges = new E[nE];
for (int j = 0; j < nV; j++) {
vertices[j] = new V(j);
}
for (int j = 0; j < nE; j++) {
int start = io.nextInt();
int end = io.nextInt();
double w = io.nextDouble();
if (end > start) {
edges[j] = new E(vertices[start], vertices[end], w);
} else {
edges[j] = new E(vertices[end], vertices[start], w);
}
}
ArrayList<E> result = compute(nV, edges);
if (result.size() > 0) {
sum = 0;
for (int i = 0; i < result.size(); i++) {
sum += result.get(i).w;
}
io.println(sum);
String[] resultStrings = new String[result.size()];
for (int i = 0; i < result.size(); i++) {
resultStrings[i] = "" + result.get(i).start.name + " " + result.get(i).end.name;
}
Arrays.sort(resultStrings);
for (int i = 0; i < result.size(); i++) {
io.printf("%s\n", resultStrings[i]);
}
} else {
io.println("Impossible");
}
}
io.close();
}
public void signJar(Jar jar) {
if (digestNames == null || digestNames.length == 0)
error("Need at least one digest algorithm name, none are specified");
if (keystoreFile == null || !keystoreFile.getAbsoluteFile().exists()) {
error("No such keystore file: " + keystoreFile);
return;
}
if (alias == null) {
error("Private key alias not set for signing");
return;
}
MessageDigest digestAlgorithms[] = new MessageDigest[digestNames.length];
getAlgorithms(digestNames, digestAlgorithms);
try {
Manifest manifest = jar.getManifest();
manifest.getMainAttributes().putValue("Signed-By", "Bnd");
// Create a new manifest that contains the
// Name parts with the specified digests
ByteArrayOutputStream o = new ByteArrayOutputStream();
manifest.write(o);
doManifest(jar, digestNames, digestAlgorithms, o);
o.flush();
byte newManifestBytes[] = o.toByteArray();
jar.putResource("META-INF/MANIFEST.MF", new EmbeddedResource(newManifestBytes, 0));
// Use the bytes from the new manifest to create
// a signature file
byte[] signatureFileBytes = doSignatureFile(digestNames, digestAlgorithms, newManifestBytes);
jar.putResource("META-INF/BND.SF", new EmbeddedResource(signatureFileBytes, 0));
// Now we must create an RSA signature
// this requires the private key from the keystore
KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
KeyStore.PrivateKeyEntry privateKeyEntry = null;
java.io.FileInputStream keystoreInputStream = null;
try {
keystoreInputStream = new java.io.FileInputStream(keystoreFile);
char[] pw = password == null ? new char[0] : password.toCharArray();
keystore.load(keystoreInputStream, pw);
keystoreInputStream.close();
privateKeyEntry =
(PrivateKeyEntry) keystore.getEntry(alias, new KeyStore.PasswordProtection(pw));
} catch (Exception e) {
error(
"No able to load the private key from the give keystore("
+ keystoreFile.getAbsolutePath()
+ ") with alias "
+ alias
+ " : "
+ e);
return;
} finally {
IO.close(keystoreInputStream);
}
PrivateKey privateKey = privateKeyEntry.getPrivateKey();
Signature signature = Signature.getInstance("MD5withRSA");
signature.initSign(privateKey);
signature.update(signatureFileBytes);
signature.sign();
// TODO, place the SF in a PCKS#7 structure ...
// no standard class for this? The following
// is an idea but we will to have do ASN.1 BER
// encoding ...
ByteArrayOutputStream tmpStream = new ByteArrayOutputStream();
jar.putResource("META-INF/BND.RSA", new EmbeddedResource(tmpStream.toByteArray(), 0));
} catch (Exception e) {
error("During signing: " + e);
}
}
