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Leo Yun Tao15,956 Points
Why must the midPoint + 1 or -1
I do not understand why must we minus 1 or add 1 when we are setting the first and the last to be the midPoint?
The first condition of our if statement tests if the midpoint is equal to our target. If so, then we are done and the function returns the correct target.
If the midpoint did not equal our target, then we know that we don't need to use the current midpoint anymore because it has already been tested as false. Then it is a simple matter of either adding or subtracting one to our midpoint to begin to use a new untested value as part of our new range of values for the next loop.