You can use these algorithms to find low and high indexes.
For Low Index:
Consider the range between low and high indexes at each step and then find the mid-index.
If the element at the mid Index is lower than the key, low will become mid + 1. This allows you to move towards the beginning of the range.
If the mid element >= the key, the high will be mid - 1. The low Index will remain the same.
If the low > high, it would indicate the first appearance of the key.
Return -1 if the key does not match the element at the low.
For High Index:
Similar results can be obtained by slightly altering the condition above for high Index
Switch the low Index to middle + 1 if the key Index of an element is lower than or equal to the Index at mid.
Switch the high Index to middle - 1 if the key element is larger than the mid.
