[Leetcode OJ] Single number bis--given an array of integers, every element appears three times except for one. Find the single one.

1 classSolution {2  Public:3     intSinglenumber (intA[],intN) {4         intBITS =sizeof(int)*8;5         intresult=0;6          for(intI=1; i<=bits; i++)7         {8            intw=0;9            intt=1;Ten             One             for(intj=0; j<n; J + +) AW + = (a[j]>> (i-1)) &T; -result+= (w%3) << (I-1); //If the other number repeats K times except for one number, change the 3 here to K  -         } the         returnresult; -     } -};

Using binary bitwise operations to solve this problem, such as the input array is [2,2,3,2]

They correspond to the binary as:

0010 (2)

0010 (2)

0011 (3)

0010 (2)

————

Corresponding bit sum: 0 0 4 1

Add all the integers corresponding to the bits and divide the remainder after 3 to get 0011 (3), which is the single number we are looking for.

For all but one occurrence of an integer, the other integers appear k times (k=2,3,4 ...), ask for a single number, or you can use the above bit arithmetic to solve the problem, just change the program 3 to K.