LeetCode：Number Complement

最新推荐文章于 2025-08-11 15:06:51 发布

Chan_Keh

最新推荐文章于 2025-08-11 15:06:51 发布

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分类专栏： LeetCode 文章标签： leetcode

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本文介绍了一种求解正整数补码的方法，并提供了一个具体的C++代码实现。通过翻转输入整数的二进制位来计算其补码，并确保了在32位带符号整数范围内的正确性。

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Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

Note:
The given integer is guaranteed to fit within the range of a 32-bit signed integer.
You could assume no leading zero bit in the integer’s binary representation.
Example 1:
Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.
Example 2:
Input: 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0.

class Solution {
public:
    int findComplement(int num) {
      vector<int>vec;
      for(int i=0;i<32;++i)
      {
          vec.push_back(0);
      }
      int st = 0;
      while(num)
      {
          vec[st++] = (num%2);
          num/=2;
      }
      int k = 31;
      while(vec[k--]==0);
      for(int j=k+1;j>=0;--j)
      {
          if(vec[j]==0)
            vec[j] = 1;
          else
            vec[j] = 0;
      }
      int res = 0;
      for(int i = 0;i<32;++i)
      {
          if(vec[i]==0)
              continue;
          else
             res += vec[i]*pow(2,i);
      }
      return res;
    }
};