Little Elephant and Order
The Little Elephant loves lucky strings. Everybody knows that the lucky string is a string of digits that contains only the lucky digits 4 and 7. For example, strings "47", "744", "4" are lucky while "5", "17", "467" are not. The Little Elephant has the strings A and B of digits. These strings are of equal lengths, that is |A| = |B|. He wants to get some lucky string from them. For this he perfor
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L1 Observation
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L4 Pseudo-code
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L5 Full solution
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solution.cppC++17
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