leetcode

Author: ayoubzulfiqar

CountOddNumbersInAnIntervalRange/count_odd_numbers_in_an_interval_range.dart

@@ -0,0 +1,104 @@
+/*
+
+
+-* 1523. Count Odd Numbers in an Interval Range *-
+
+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
+
+
+*/
+
+class A {
+  int countOdds(int high, int low) {
+    return ((high + 1) ~/ 2) - (low ~/ 2);
+  }
+}
+
+class B {
+  int countOdds(int high, int low) {
+    if ((high & 1) == 0) high--;
+    return (low > high) ? 0 : (high + 1) ~/ 2 - (low ~/ 2);
+  }
+}
+
+class C {
+  int countOdds(int high, int low) {
+    int total = high - low + 1;
+    if (total % 2 == 0)
+      return total ~/ 2;
+    else {
+      if (low % 2 != 0)
+        return total ~/ 2 + 1;
+      else
+        return total ~/ 2;
+    }
+  }
+}
+
+class D {
+  int countOdds(int low, int high) {
+    if (low % 2 == 0 && high % 2 == 0)
+      return (high - low) ~/ 2;
+    else {
+      int firstOddNumber = low % 2 == 0 ? low + 1 : low;
+      return (high - firstOddNumber) ~/ 2 + 1;
+    }
+  }
+}
+
+class F {
+  int countOdds(int high, int low) {
+    int count = 0;
+    for (int i = low; i <= high; i++) {
+      if (i % 2 != 0) count++;
+    }
+    return count;
+  }
+}
+
+class G {
+  int countOdds(int low, int high) {
+    int result = 0;
+    if ((low & 1) == 0) {
+      result++;
+      low++;
+    }
+    if ((high & 1) == 0) {
+      result++;
+      high--;
+    }
+    result += (high - low) ~/ 2;
+
+    return result;
+  }
+}
+
+class H {
+  int countOdds(int low, int high) {
+    if (low % 2 == 0 && high % 2 == 0) {
+      return (high - low) ~/ 2;
+    } else if (low % 2 != 0 && high % 2 != 0) {
+      return 2 + (high - low) ~/ 2 - 1;
+    } else {
+      return 1 + (high - low) ~/ 2;
+    }
+  }
+}

CountOddNumbersInAnIntervalRange/count_odd_numbers_in_an_interval_range.go

@@ -0,0 +1,30 @@
+package main
+
+func countOdds1(low int, high int) int {
+
+	return ((high + 1) / 2) - (low / 2)
+}
+
+func countOdds2(low int, high int) int {
+	if (high & 1) == 0 {
+		high--
+	}
+	if low > high {
+		return 0
+	}
+	return ((high + 1) / 2) - (low / 2)
+}
+
+func countOdds3(low int, high int) int {
+	var total int = high - low + 1
+	if total%2 == 0 {
+		return total / 2
+	} else {
+		if low%2 != 0 {
+			return (total / 2) + 1
+
+		}
+	}
+	return total / 2
+
+}

CountOddNumbersInAnIntervalRange/count_odd_numbers_in_an_interval_range.md

@@ -0,0 +1,104 @@
+# 🔥 6 Approaches 🔥 || Simple Fast and Easy || with Explanation
+
+## Intuition
+
+we will calculate all odd number from 1 to low-1 and 1 to high;
+why low-1??
+because we want include our low value.
+
+## Approach
+
+Total odd number between 1 and low - 1 is low/2.
+Total odd number between 1 and high is (high + 1 ) / 2.
+For getting answer we will do
+Total odd number between 1 and high - Total odd number between 1 and low - 1
+
+## Complexity
+
+### - Time complexity:O(1)
+
+### - Space complexity:O(1)
+
+## Code -1
+
+```dart
+class Solution {
+  int countOdds(int high, int low) {
+    return ((high + 1) ~/ 2) - (low ~/ 2);
+  }
+}
+```
+
+## Code -2
+
+```dart
+class Solution {
+  int countOdds(int high, int low) {
+    if ((high & 1) == 0) high--;
+    return (low > high) ? 0 : (high + 1) ~/ 2 - (low ~/ 2);
+  }
+}
+```
+
+## Code -3
+
+```dart
+class Solution {
+  int countOdds(int high, int low) {
+    int total = high - low + 1;
+    if (total % 2 == 0)
+      return total ~/ 2;
+    else {
+      if (low % 2 != 0)
+        return total ~/ 2 + 1;
+      else
+        return total ~/ 2;
+    }
+  }
+}
+```
+
+## Code -4
+
+```dart
+class Solution {
+  int countOdds(int low, int high) {
+    if (low % 2 == 0 && high % 2 == 0)
+      return (high - low) ~/ 2;
+    else {
+      int firstOddNumber = low % 2 == 0 ? low + 1 : low;
+      return (high - firstOddNumber) ~/ 2 + 1;
+    }
+  }
+}
+```
+
+## Code -5
+
+```dart
+class Solution {
+  int countOdds(int high, int low) {
+    int count = 0;
+    for (int i = low; i <= high; i++) {
+      if (i % 2 != 0) count++;
+    }
+    return count;
+  }
+}
+```
+
+## Code -6
+
+```dart
+class Solution {
+  int countOdds(int low, int high) {
+    if (low % 2 == 0 && high % 2 == 0) {
+      return (high - low) ~/ 2;
+    } else if (low % 2 != 0 && high % 2 != 0) {
+      return 2 + (high - low) ~/ 2 - 1;
+    } else {
+      return 1 + (high - low) ~/ 2;
+    }
+  }
+}
+```

README.md

@@ -209,8 +209,8 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [**2306.** Naming a Company](NamingACompany/naming_a_company.dart)
 - [**1162.** As Far from Land as Possible](AsFarFromLandAsPossible/as_far_from_land_as_possible.dart)
 - [**1129.** Shortest Path with Alternating Colors](ShortestPathWithAlternatingColors/shortest_path_with_alternating_colors.dart)
-
 - [**2477.** Minimum Fuel Cost to Report to the Capital](MinimumFuelCostToReportToTheCapital/minimum_fuel_cost_to_report_to_the_capital.dart)
+- [**1523.** Count Odd Numbers in an Interval Range](CountOddNumbersInAnIntervalRange/count_odd_numbers_in_an_interval_range.dart)
 
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