📘 Lesson · Lesson 52
Binary Search
Binary Search
Binary Search Program in Java
Binary search finds an item in a SORTED array by repeatedly halving the search range — much faster than checking each element.
Java Program
int[] a = {1, 3, 5, 7, 9, 11};
int key = 7, low = 0, high = a.length - 1, pos = -1;
while (low <= high) {
int mid = (low + high) / 2;
if (a[mid] == key) { pos = mid; break; }
else if (a[mid] < key) low = mid + 1;
else high = mid - 1;
}
System.out.println("Found at index " + pos);Output
Found at index 3
How it Works
- Check the middle; if too small, search the right half, else the left.
- Works only on sorted arrays; very fast (O(log n)).
Summary
- Binary search finds an item in a SORTED array by repeatedly halving the search range — much faster than checking each element.
Binary Search Program in Java
Binary search एक SORTED array में बार-बार search range आधा करके item ढूंढता है — हर element जाँचने से बहुत तेज़।
Java Program
int[] a = {1, 3, 5, 7, 9, 11};
int key = 7, low = 0, high = a.length - 1, pos = -1;
while (low <= high) {
int mid = (low + high) / 2;
if (a[mid] == key) { pos = mid; break; }
else if (a[mid] < key) low = mid + 1;
else high = mid - 1;
}
System.out.println("Found at index " + pos);Output
Found at index 3
कैसे काम करता है
- बीच का जाँचें; छोटा हो तो दायाँ आधा, वरना बायाँ search करें।
- सिर्फ sorted arrays पर; बहुत तेज़ (O(log n))।
सारांश
- Binary search एक SORTED array में बार-बार search range आधा करके item ढूंढता है — हर element जाँचने से बहुत तेज़।