Java 即使条件不再满足，while循环仍将继续

我想得到两个数字的索引，这两个数字加起来就是目标

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但是当它进入循环时，即使index1和index2都不是-1，它仍然保持循环

问题是在递归调用之后，您的函数不会返回，因此循环执行两次。这就是为什么即使条件变为false，循环似乎仍在执行

您需要返回递归调用的结果

public class SumOfTwoNum {
    public int[] twoSum(int[] numbers, int target) {
        int med = numbers.length/2;
        if (numbers[med] > target) {
            twoSum(Arrays.copyOfRange(numbers,0,med), target);
        }
        int remainNum;
        int index1 = -1;
        int index2 = -1;
        while (index1 == -1 && index2 == -1) {
            remainNum = target-numbers[med];
            if (remainNum > numbers[med]) {
                index2 = Arrays.binarySearch(numbers,med,numbers.length,remainNum);
                index1 = med;
            } else {
                index1 = Arrays.binarySearch(numbers,0,med,remainNum);
                index2 = med;
            }
            //here I get index1=0 and index2=1, but the loop doesn't stop
            med --;

        }
        return new int[] {index1, index2};
    }

    public static void main(String[] args) {
        SumOfTwoNum s = new SumOfTwoNum();
        System.out.println(Arrays.toString(s.twoSum(new int[] {2,7,11,15},9)));
        //what I hope to get here is {0,1}, but it returns {-1,2}
    }
}

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问题是在递归调用之后，函数不会返回，所以循环执行两次。这就是为什么即使条件变为false，循环似乎仍在执行

您需要返回递归调用的结果

public class SumOfTwoNum {
    public int[] twoSum(int[] numbers, int target) {
        int med = numbers.length/2;
        if (numbers[med] > target) {
            twoSum(Arrays.copyOfRange(numbers,0,med), target);
        }
        int remainNum;
        int index1 = -1;
        int index2 = -1;
        while (index1 == -1 && index2 == -1) {
            remainNum = target-numbers[med];
            if (remainNum > numbers[med]) {
                index2 = Arrays.binarySearch(numbers,med,numbers.length,remainNum);
                index1 = med;
            } else {
                index1 = Arrays.binarySearch(numbers,0,med,remainNum);
                index2 = med;
            }
            //here I get index1=0 and index2=1, but the loop doesn't stop
            med --;

        }
        return new int[] {index1, index2};
    }

    public static void main(String[] args) {
        SumOfTwoNum s = new SumOfTwoNum();
        System.out.println(Arrays.toString(s.twoSum(new int[] {2,7,11,15},9)));
        //what I hope to get here is {0,1}, but it returns {-1,2}
    }
}

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你可以为它创建一个布尔标志吗？基本上，

boolean finished=false

在您的while

while（！finished）

上，然后在while块的底部或您认为更好的地方添加

finished=index1！=-1&&index2！=-1

。您可以为此创建一个布尔标志吗？基本上，

boolean finished=false

在您的while

while（！finished）

上，然后在while块的底部或您认为更好的地方添加

finished=index1！=-1&&index2！=-1

。