I’ve officially started my Top 150 LeetCode journey to strengthen my foundations in Data Structures & Algorithms.
✅ Progress: 3 / 150 Problems Solved
Rather than rushing through problems, my focus is on understanding patterns, improving reasoning, and writing cleaner solutions over time.
🧩 Problems Solved Today
1️⃣ Merge Sorted Array
Approach:
Merged elements from the second array into the first and applied sorting to maintain order.
Key Learning:
A working solution isn’t always the optimal one. This problem introduced the importance of thinking about pointer-based merging instead of relying purely on sorting.
class Solution {
public:
vector<int> merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
for(int i = m; i < m + n; i++) {
nums1[i] = nums2[i - m];
}
for(int i = 0; i < m + n - 1; i++) {
for(int j = 0; j < m + n - i - 1; j++) {
if(nums1[j] > nums1[j+1]) {
swap(nums1[j], nums1[j+1]);
}
}
}
return nums1;
}
};
2️⃣ Remove Element
Approach:
Used a write pointer (idx) to overwrite unwanted values in-place.
Key Learning:
Many array problems reduce to maintaining a correct write index rather than deleting elements.
class Solution {
public:
int removeElement(vector<int>& nums, int val) {
int idx = 0;
for(int i = 0; i < nums.size(); i++){
if(nums[i] != val){
nums[idx++] = nums[i];
}
}
return idx;
}
};
3️⃣ Remove Duplicates from Sorted Array
Approach:
Compared current element with the previous one and stored only unique values using a pointer.
Key Learning:
Sorted arrays unlock simpler logic — recognizing structure in input data is powerful.
class Solution {
public:
int removeDuplicates(vector<int>& nums) {
if(nums.empty()) return 0;
int idx = 1;
for(int i = 1; i < nums.size(); i++) {
if(nums[i] != nums[i-1]) {
nums[idx++] = nums[i];
}
}
return idx;
}
};
🧠 Reflection
Early DSA problems look simple, but they build essential habits:
- thinking in-place,
- minimizing extra memory,
- recognizing reusable patterns.
This challenge isn’t about speed — it’s about consistent improvement.
📍 Next Target: Top 150 continues…
If you’re also working on DSA or building consistency in problem solving, let’s grow together.
🔗 GitHub — https://github.com/CodeWithDeeksh
🐦 X — https://x.com/deekshithax
One problem at a time. Consistency over intensity.