ADVANCED DATA STRUCTURES PROGRAM • LEVEL 13 — ADVANCED SEARCHING

Search an Unbounded-Style Array Exponentially

Learn how to search an unbounded-style array exponentially using a clear C program.

IntermediateBinary searchSearch boundaries

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

Index = 5

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int values[] = {2, 3, 4, 10, 40, 55, 70, 90}, target = 55, bound = 1;
    while (bound < 8 && values[bound] < target) bound *= 2;
    int low = bound / 2, high = bound < 7 ? bound : 7;
    while (low <= high) { int middle = low + (high - low) / 2; if (values[middle] == target) { printf("Index = %d\n", middle); break; } if (values[middle] < target) low = middle + 1; else high = middle - 1; }
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

Index = 5

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Double the bound until it crosses the target, then binary-search that bounded interval.
Display the computed result.

Double the bound until it crosses the target, then binary-search that bounded interval.

EFFICIENCY

Time and space complexity

Time complexity

O(log position)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.