# Need to check whether index is within the bound after it runs out of the loop

Erratum

The supplied solution isn’t complete and will get into run-time error:
i.e. Add the following lines in the main method in the solution section.

``````int low = find_low_index(array, 8);
int high = find_high_index(array, 8);
System.out.println("LowIndex of 8 : "+ low);
System.out.println("HighIndex of 8 : "+ high);
``````

Leetcode

I wasn’t able to find corresponding Leetcode example for this problem.

Correction & Alternative solution

``````class findLowHigh{
static int find_low_index(List<Integer> arr, int key) {
int min = 0;
int max = arr.size() - 1;
while (min <= max) {
int mid = min + (max - min) / 2;
if (arr.get(mid) < key) {
min = mid + 1;
} else {
max = mid - 1;
}
}
// Must check whether index is within the bound
if (min < arr.size() && arr.get(min) == key) return min;
return -1;
}

// Possible alternative solution
static int find_high_index(List<Integer> arr, int key) {
int min = 0;
int max = arr.size() - 1;
while (min <= max) {
int mid = min + (max - min) / 2;
if (arr.get(mid) == key) {
// Instead of checking value of min/max after escaping the while loop,
//  We can do it here.
if (arr.get(max) == key) {
return max;
} else {
min = mid;
max = max - 1;
}
} else if (arr.get(mid) < key) {
min = mid + 1;
} else {
max = mid - 1;
}
}
return -1;
}
}``````

Thank you for your valuable input! We are happy to hear from you.

We’d like you to check it out again. The mistake is rectified and the test cases will now run just fine using the solution code provided.

If you have any further queries, please let us know.

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