Formatted question description: https://leetcode.ca/all/1012.html

1012. Complement of Base 10 Integer (Easy)

Every non-negative integer N has a binary representation.  For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on.  Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1.  For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of it's binary representation as a base-10 integer.

 

Example 1:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

 

Note:

1. 0 <= N < 10^9

Companies:
Cloudera

Related Topics:
Math

Solution 1.

// OJ: https://leetcode.com/problems/complement-of-base-10-integer/

// Time: O(1)
// Space: O(1)
class Solution {
public:
    int bitwiseComplement(int N) {
        if (!N) return 1;
        unsigned mask = ~0;
        while (mask & N) mask <<= 1;
        return ~N & ~mask;
    }
};

Java

• Java
• C++
• Python

• class Solution {
      public int numDupDigitsAtMostN(int N) {
          if (N <= 10)
              return 0;
          int duplicates = 0;
          int length = String.valueOf(N).length();
          for (int i = 2; i < length; i++)
              duplicates += dupNums(i);
          Set<Integer> usedDigits = new HashSet<Integer>();
          int curNum = (int) Math.pow(10, length - 1);
          int curLength = length - 1;
          int unit = curNum;
          boolean flag = false;
          while (unit > 1) {
              int lastDigit = N / unit % 10;
              int upperBound = N / unit * unit;
              while (curNum < upperBound) {
                  int curDigit = curNum / unit % 10;
                  int curCount = 0;
                  if (!usedDigits.contains(curDigit)) {
                      curCount = 1;
                      int start = 9 - usedDigits.size();
                      for (int i = 0; i < curLength; i++)
                          curCount *= start - i;
                  }
                  duplicates += unit - curCount;
                  curNum += unit;
              }
              if (usedDigits.add(lastDigit)) {
                  curLength--;
                  unit /= 10;
              } else {
                  flag = true;
                  break;
              }
          }
          if (flag)
              duplicates += N - curNum + 1;
          else {
              while (curNum <= N) {
                  int lastDigit = curNum % 10;
                  if (usedDigits.contains(lastDigit))
                      duplicates++;
                  curNum++;
              }
          }
          return duplicates;
      }
  
      public int dupNums(int length) {
          int distincts = 9;
          for (int i = 1; i < length; i++)
              distincts *= 10 - i;
          return 9 * (int) Math.pow(10, length - 1) - distincts;
      }
  }
  

• // OJ: https://leetcode.com/problems/complement-of-base-10-integer/
  // Time: O(1)
  // Space: O(1)
  class Solution {
  public:
      int bitwiseComplement(int N) {
          if (!N) return 1;
          unsigned mask = ~0;
          while (mask & N) mask <<= 1;
          return ~N & ~mask;
      }
  };
  

• class Solution(object):
      def bitwiseComplement(self, N):
          """
          :type N: int
          :rtype: int
          """
          return int("".join(map(lambda x :"0" if x == "1" else "1", bin(N)[2:])), 2)
  

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