Given three integers a, b and c, find the first occurrence of c in a/b after the decimal point. If it does not exists, print -1.
Input : a = 2 b = 3 c = 6 Output : 1 Explanation: 0.666666.. so 6 occurs at first place of a/b after decimal point Input : a = 1 b = 4 c = 5 Output : 2 Explanation: 1 / 4 = 0.25 which gives 5's position to be 2.
A naive approach will be to perform the division and keep the decimal part and iterate and check if the given number exists or not. This will not work well when divisions such as 2/3 is done as it yields 0.666666666, but in programming language it will round it off to 0.666667 so we get a 7 also which does not exists in the original a/b
An efficient approach will be the mathematical one, if we modulate every-time a by b and multiply it with 10 we get the integers after the decimal part every-time. The number of modulations required will be b as it will have a maximum of b integers after decimal point. So, we compare it with c and get our desired value if it is present.
Below is the implementation of the above approach :
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