我几天来一直在测试的东西有问题。
全部使用栈和队列
Sample.txt : My mom and dad both think I will do good at my gig tomorrow.
我有一个 GUI,它附加了一个文件并为回文解析文件。例如,我想,
我可以找到 mom
作为回文,并且由于 mom.length()
== to 3
我会捕获第三个来自 mom
的 token ,在本例中为 both
。我能够正确地捕获所有这些回文,只是不知道如何遍历我还没有“读过”的标记?
我的方法是,
public void fileDecode() throws FileNotFoundException
{
while(scanInput.hasNext())
{
int counter = 0;
int nextPalindrome = 0;
String token = scanInput.next();
Stack<Character> stk = new Stack<Character>();
Queue<Character> que = new LinkedList<Character>();
for (int i = 0; i < token.length(); ++i)
{
stk.push(token.charAt(i));
que.add(token.charAt(i));
}
for (int j = 0; j < token.length(); ++j)
{
char tempStk = stk.pop();
char tempQue = que.remove();
if (tempStk == tempQue)
{
counter++;
}
}
if (counter == token.length())
{
//build.append(token + " "); #if i want to see the palindromes
nextPalindrome = token.length(); //the length/distance of the token desired
}
}
}
}
最佳答案
just at a loss on how i would traverse tokens that i haven't 'read' in yet?
您阅读并跳过它们。只需使用通常为 0 的局部变量,但是一旦找到回文,就将其设置为回文的长度。然后在检查逻辑之前检查这个变量并在它大于 0 时继续循环。
// Idea: there are 3 cases:
// 1. tokensToSkip is 0: process as normal (check for palindromeness)
// 2. tokensToSkip is 1: decrement it to 0, but process as normal
// 3. tokensToSkip is 2, 3, 4...: decrement it and skip (continue the while)
// Note that tokensToSkip will never be negative.
// Will skip tokensToSkip - 1 tokens
int tokensToSkip = 0;
while(scanInput.hasNext()) {
String token = scanInput.next();
// instead of the next two lines we could just have:
// if (--tokensToSkip > 0) continue;
// only once, notice the -- operator in front.
//
// This would almost always work, but if tokensToSkip = Integer.MIN_VALUE
// decrementing it will cause negative overflow and thus tokensToSkip will
// become Integer.MAX_VALUE! To prevent this we have a check.
if (tokensToSkip > 0) tokensToSkip--;
// here tokensToSkip is already decremented, so this check is different
// from the one above. For example is tokensToSkip == 1 before the line
// above, now it is tokensToSkip == 0 and this second check fails.
if (tokensToSkip > 0) continue;
if (isPalindrome(token)) {
tokensToSkip = token.length();
}
// ... other stuff ...
}
顺便说一下,一个更有效的实现isPalindrome()
的方法是:
static boolean isPalindrome(String s) {
for (int i = 0; i < s.length() / 2; i++) {
if (s.charAt(i) != s.charAt(s.length() - i - 1)) {
return false;
}
}
return true;
}
关于java - 扫描并获取特定 token ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33202981/