Algorithm-left rotation Array

Define the left rotation operation of the string: Move several characters before the string to the end of the string. For example, the string abcdef is rotated two places to the left to obtain the string cdefab. Idea: such as the left rotation of 2 places, first "reverse" The 2 places, then "reverse" the remaining N-2 bit, and finally "reverse" all N places.

 

The algorithm is as follows:

/// <Summary> <br/> // define the left rotation operation of the string: Move several characters before the string to the end of the string. <Br/> // If the string abcdef is left rotated by two digits, the string cdefab is obtained. <Br/> /// </Summary> <br/> // <Param name = "A"> Operation Array </param> <br/> // <param name = "N"> array length </param> <br/> // <Param name = "K"> Number of left-rotated digits </param> <br/> static void test (INT [], int N, int K) <br/>{< br/> K % = N; <br/> If (k = 0) return; </P> <p> reverse (A, 0, k-1); <br/> reverse (A, k, n-1 ); <br/> reverse (A, 0, n-1 ); <br/>}</P> <p> // <summary> <br/> // reverse <br/> /// </Summary> <br/> /// <Param name = "A"> Operation Array </param> <br/> /// <Param name = "begin"> reverse the start position </param> <br/> // <Param name = "end"> reverse the end position </param> <br/> static void reverse (INT [], int begin, int end) <br/>{< br/> while (begin <End) <br/>{< br/> int temp = A [end]; <br/> A [end] = A [begin]; <br/> A [begin] = temp; </P> <p> begin ++; <br/> end --; <br/>}< br/>}

The code is clear and concise.

End.