想不出为什么我的 Java 代码会无限循环

Question

I tried to do this LeetCode daily challenge but I've found out that my code loops infinitely.

I looked through it multiple times, but I cannot find where the problem is. If anyone could spot it, please answer.

public int longestValidParentheses(String s) {
    int count, highestOne = 0, index = 0;
    boolean isSevered = false;
    boolean theEnd = false;
    while(!theEnd) {
        count = 0;
        while(!isSevered) {
            if(index<s.length()-2) {
                if(s.charAt(index) == '(' & s.charAt(index++) == ')') {count = count + 2;index = index+2;}
                else {isSevered = true;}}
            else theEnd=true;isSevered=true;
        }
        highestOne = count;
    }
    return highestOne;
}

Answer 1

I have 2 suggestions for you:

1. Use indentation and do not write if/else on the same line as the code associated with them
2. Always, ALWAYS use bracelets, even if you have only a single command. I think one of the wrongs java did is letting the programmers the free not to use bracelets if there is just a single command after it. It confusing.

So you have 2 mistakes here that make your code run for infinity:

1. isSevered will always be true after one loop exactly, as you change it to true no matter what happens as it is outside the if else statements, hence the reason I wrote the 2 advices above.
2. You never changing isSeveres or theEnd at the outside loop. Meaning that if isSevers is true and theEnd is false, you will never enter the internal while and will never exit the outside while .

The two of those combined means that if the condition that make theEnd be initialized with true won't happen at the first run, you will be stuck with infinity loop.