Copy from both ends simultaneously toward the center.

bidirectional_copy.java

// Bidirectional Copy (from both ends toward center)
// Used for reversing arrays or merging sorted arrays
// Processes from opposing ends simultaneously
public static void bidirectionalCopy(int[] src, int srcStart, int srcEnd, 
                                      int[] dest, int destStart, int destEnd) {
    int left = srcStart;
    int right = srcEnd;
    int destLeft = destStart;
    int destRight = destEnd;
    
    while (left <= right) {
        dest[destLeft++] = src[left++];
        if (left <= right) {
            dest[destRight--] = src[right--];
        }
    }
}

// Example: Reverse array elements
// Original: [1, 2, 3, 4, 5]
// Bidirectional copy from indices 0-4 to indices 4-0
// Result:   [5, 4, 3, 2, 1] (reversed)

// Example: Merge sorted arrays
// Left half:  [1, 3, 5]
// Right half: [2, 4, 6]
// Bidirectional merge works from both ends to build sorted result