1523. Count Odd Numbers in an Interval Range.md

1523. Count Odd Numbers in an Interval Range

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the first one in Biweekly Contest 31.

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Difficulty : Easy

Related Topics : Math

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Given two non-negative integers low and high. Return the count of odd numbers between low and high (inclusive).

Example 1:

Input: low = 3, high = 7
Output: 3
Explanation: The odd numbers between 3 and 7 are [3,5,7].

Example 2:

Input: low = 8, high = 10
Output: 1
Explanation: The odd numbers between 8 and 10 are [9].

Constraints:

• 0 <= low <= high <= 10^9

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Solution

• mine
  • Java
    • Runtime: 0 ms, faster than 100.00%, Memory Usage: 36.4 MB, less than 100.00% of Java online submissions

      //O(1)time
      //O(1)space
      public int countOdds(int low, int high) {
          int res = 0;
          if(low % 2 != 0) res++;
          if(high % 2 != 0) res++;
          res += (high - low - res) / 2;
          return res;
      }
      

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