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Problem Solution 1. Pass all the leading whitespaces 2. Flag the sign if it is present in the beginning 3. Go through the rest of the string or until nonnumeric string is seen Recognize numeric string using ASCII table. Every time the code reads a character in the given string, it needs to determine if the number will be out of the 32-bit unsigned integer bound. The way that we are forming the n..

Problem Solution We can change the direction to right(1,0), down(0,1), left(0,-1) and up(0,-1), and rotating in that order. Set these pairs of movements into a list so that they can be easily accessed in the right order. The code should keep printing until it meets one of two conditions: The row number of column number goes out of boundaries of the matrix The position has already been visited Ch..

Problem Solution Could use nested for-loops but that will end up with O(n^2) complexity. Arrays have constant complexity when accessing a known index. However arrays can have up to O(n) complexity when searching while hashmap has near constant complexity. In order to improve the speed, make a hashmap by mapping each element in nums to its index number. When iterating through the array, get the c..

Problem Solution Max distance that we can move at a time is 2. Look at the index value larger than current position by 2. If the value is 0, move 2 times and add a jump. If the value is 1, move just one time and add a jump. (If we are at a position where only one number is left in the array, it is not possible to move up 2 times... so just add one jump and end the loop.) import java.io.*; import..

Problem Need two integers: one for keeping track of the number of valleys, and another for tracking current position. Let the hiker start at position 0. "U" represents +1, "D" represents -1. Since we only care about the number of valleys completed and not mountains, we want to know when the hiker climbs out of a valley... which would be the moment position -1 becomes 0. import java.io.*; import ..