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3SUM LEETCODE SOLUTION JAVA
When it comes to coding challenges, LeetCode is a popular platform that offers a wide range of problems to solve. One such problem that often stumps programmers is the 3SUM problem. In this article, we will explore the 3SUM problem, discuss how to approach it, and provide a Java solution to tackle it effectively.
Understanding the 3SUM Problem
The 3SUM problem is a classic algorithmic problem that asks us to find all unique triplets in an array that sum up to a target value. In other words, given an array of integers, we need to find all combinations of three numbers that add up to a specific target sum.
Approaching the 3SUM Problem
One common approach to solving the 3SUM problem involves using a two-pointer technique. Here’s a high-level overview of how this technique works:
- Sort the input array in non-decreasing order.
- Iterate through the array, fixing one element as the target value.
- Use two pointers to find the other two elements that sum up to the target value.
- Move the pointers accordingly based on whether the sum is greater or less than the target value.
Java Solution for the 3SUM Problem
Let’s take a look at a Java solution for the 3SUM problem using the two-pointer technique:
“`java
public List<List> threeSum(int[] nums) {
List<List> result = new ArrayList();
Arrays.sort(nums);
for (int i = 0; i 0 && nums[i] != nums[i – 1])) {
int lo = i + 1, hi = nums.length – 1, target = -nums[i];
while (lo < hi) {
if (nums[lo] + nums[hi] == target) {
result.add(Arrays.asList(nums[i], nums[lo], nums[hi]));
while (lo < hi && nums[lo] == nums[lo + 1]) lo++;
while (lo < hi && nums[hi] == nums[hi – 1]) hi–;
lo++;
hi–;
} else if (nums[lo] + nums[hi] < target) {
lo++;
} else {
hi–;
}
}
}
}
return result;
}
“`
Conclusion
In conclusion, the 3SUM problem is a challenging algorithmic problem that can be effectively solved using the two-pointer technique.
. By understanding the problem, approaching it strategically, and implementing a Java solution like the one provided above, programmers can successfully tackle this problem on platforms like LeetCode. Remember to practice regularly and explore different approaches to enhance your problem-solving skills.
