Two Pointer Technique on Arrays in DSA C - Build from Scratch

Two Pointer Technique on Arrays

📖 Scenario: You are working with a sorted list of numbers representing daily temperatures in Celsius. You want to find two days where the temperatures add up to a specific target value.

🎯 Goal: Build a program that uses the two pointer technique to find if there are two numbers in the array that add up to the target temperature.

📋 What You'll Learn

Create an integer array called temps with these exact values: 2, 4, 7, 11, 15, 20

Create an integer variable called target and set it to 18

Use two integer pointers left and right to scan the array from both ends

Print "Found pair: X and Y" if two numbers add up to target, else print "No pair found"

💡 Why This Matters

🌍 Real World

Finding pairs of values that meet a condition is common in data analysis, such as matching budgets, temperatures, or scores.

💼 Career

Two pointer technique is a fundamental skill for coding interviews and efficient array processing in software development.

1

Create the temperature array

Create an integer array called temps with these exact values: 2, 4, 7, 11, 15, 20

DSA C

// Create the integer array temps with values 2, 4, 7, 11, 15, 20
// Your code here

Hint

Use int temps[] = {2, 4, 7, 11, 15, 20}; to create the array.

2

Set the target sum

Create an integer variable called target and set it to 18

DSA C

#include 

int main() {
    int temps[] = {2, 4, 7, 11, 15, 20};
    // Create the integer variable target and set it to 18
    // Your code here
    return 0;
}

Hint

Use int target = 18; to create the target variable.

3

Implement the two pointer search

Create two integer variables called left and right. Set left to 0 and right to 5. Use a while loop with condition left < right. Inside the loop, calculate the sum of temps[left] and temps[right]. If the sum equals target, break the loop. If the sum is less than target, increment left. Otherwise, decrement right.

DSA C

#include 

int main() {
    int temps[] = {2, 4, 7, 11, 15, 20};
    int target = 18;
    // Initialize left and right pointers
    // Use a while loop to find two numbers that add to target
    // Your code here
    return 0;
}

Hint

Use two pointers starting at the ends of the array and move them based on the sum compared to target.

4

Print the result

After the loop, use an if statement to check if the variable found is 1. If yes, print "Found pair: X and Y" where X and Y are temps[left] and temps[right]. Otherwise, print "No pair found".

DSA C

Hint

Use printf to display the found pair or no pair message.