Codility_L1_BinaryGap

Find longest sequence of zeros in binary representation of an integer.

A binary gap within a positive integer N is any maximal sequence of consecutive zeros that is surrounded by ones at both ends in the binary representation of N.

For example, number 9 has binary representation 1001 and contains a binary gap of length 2. The number 529 has binary representation 1000010001 and contains two binary gaps: one of length 4 and one of length 3. The number 20 has binary representation 10100 and contains one binary gap of length 1. The number 15 has binary representation 1111 and has no binary gaps. The number 32 has binary representation 100000 and has no binary gaps.

Write a function:

class Solution { public int solution(int N); }

that, given a positive integer N, returns the length of its longest binary gap. The function should return 0 if N doesn't contain a binary gap.

For example, given N = 1041 the function should return 5, because N has binary representation 10000010001 and so its longest binary gap is of length 5. Given N = 32 the function should return 0, because N has binary representation '100000' and thus no binary gaps.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [1..2,147,483,647].

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題目是要我們去抓取轉為二進位後的結果在1跟1之間的0總數長度最大的數值

以 525 binary為 1000010001 來說

含有兩種binary gap分別為 4 跟 3此時就要取4

Code_ver.1  (93%)

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using System; // you can also use other imports, for example: // using System.Collections.Generic; // you can write to stdout for debugging purposes, e.g. // Console.WriteLine("this is a debug message"); using System.Collections.Generic; using System.Linq; class Solution { public int solution(int N) { // write your code in C# 6.0 with .NET 4.5 (Mono) int gap = 0; List<int> lsGap = new List<int>(); bool IsOne = false; int sort = 0; int SumDigit = 0; while(N!=0) { int mod = N%2; N/=2; IsOne = (mod==1); if(IsOne && sort==0) { SumDigit = 0; sort++; } else { if(sort>0 && !IsOne) { SumDigit++; } else { lsGap.Add(SumDigit); SumDigit=0; } } } gap = lsGap.Max(); return gap; } }

後來發現透過Linq語法取Max沒有必要調整掉就可100%

Code_ver.2  (100%)

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using System; // you can also use other imports, for example: // using System.Collections.Generic; // you can write to stdout for debugging purposes, e.g. // Console.WriteLine("this is a debug message"); using System.Collections.Generic; using System.Linq; class Solution { public int solution(int N) { // write your code in C# 6.0 with .NET 4.5 (Mono) int gap = 0; int max_gap = 0; //List<int> lsGap = new List<int>(); bool IsOne = false; int sort = 0; int SumDigit = 0; while(N!=0) { int mod = N%2; N/=2; IsOne = (mod==1); if(IsOne && sort==0) { SumDigit = 0; sort++; } else { if(sort>0 && !IsOne) { SumDigit++; } else { //lsGap.Add(SumDigit); max_gap = SumDigit; SumDigit=0; if(max_gap>gap) { gap = max_gap; } } } } //gap = lsGap.Max(); return gap; } }