Java Solution to LeetCode 2085: Count Common Words With One Occurrence

Day 66 of #100DaysOfLeetCode 💻✅ Solved #3427. Sum of Variable Length Subarrays problem in Java. Approach: • Iterated through each index of the array • Determined the starting index using i - nums[i] • Ensured the start index does not go below 0 • Calculated sum of elements from start to current index i • Added each subarray sum to the total Performance: ✓ Runtime: 1 ms (Beats 99.90% submissions) ✓ Memory: 45.22 MB (Beats 56.30% submissions) Key Learning: ✓ Practiced handling variable-length subarrays ✓ Improved understanding of index-based range calculations ✓ Strengthened nested loop logic for array problems Learning one problem every single day 🚀 #Java #LeetCode #DSA #Arrays #PrefixSum #ProblemSolving #CodingJourney #100DaysOfCode

Day 90 of #100DaysOfLeetCode 💻✅ Solved #42. Trapping Rain Water problem in Java. Approach: • Used Two Pointer technique • Maintained leftMax and rightMax boundaries • Calculated trapped water based on smaller side • Accumulated water while traversing Performance: ✓ Runtime: 0 ms (Beats 100.00% submissions) 🚀 ✓ Memory: 47.70 MB (Beats 72.36% submissions) Key Learning: ✓ Mastered Two Pointer approach for complex problems ✓ Learned optimal water trapping strategy ✓ Improved understanding of boundary-based calculations Learning one problem every single day 🚀 #Java #LeetCode #DSA #TwoPointers #Arrays #ProblemSolving #CodingJourney #100DaysOfCode

Day 70 of #100DaysOfLeetCode 💻✅ Solved #3136. Valid Word problem in Java. Approach: • Checked if the word length is at least 3 • Traversed each character in the string • Ensured all characters are either letters or digits • Checked for presence of at least one vowel • Checked for presence of at least one consonant • Returned true only if all conditions are satisfied Performance: ✓ Runtime: 1 ms (Beats 99.62% submissions) 🚀 ✓ Memory: 43.08 MB (Beats 93.16% submissions) Key Learning: ✓ Practiced string validation with multiple conditions ✓ Learned efficient use of built-in character functions ✓ Strengthened logic building for edge case handling Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #ProblemSolving #CodingJourney #100DaysOfCode

Day 68 of #100DaysOfLeetCode 💻✅ Solved #977. Squares of a Sorted Array problem in Java. Approach: • Traversed the array and squared each element • Used Arrays.sort() to sort the squared values • Returned the sorted array as the result Performance: ✓ Runtime: 10 ms (Beats 37.38% submissions) ✓ Memory: 47.98 MB (Beats 18.78% submissions) Key Learning: ✓ Practiced array transformation and sorting ✓ Learned how squaring affects order in sorted arrays ✓ Understood the importance of optimizing from O(n log n) to O(n) using two pointers Learning one problem every single day 🚀 #Java #LeetCode #DSA #Arrays #Sorting #ProblemSolving #CodingJourney #100DaysOfCode

Day 82 of #100DaysOfLeetCode 💻✅ Solved #11. Container With Most Water problem in Java. Approach: • Used Two Pointer technique • Calculated area using min height and width • Moved pointer with smaller height inward • Tracked maximum area throughout Performance: ✓ Runtime: 5 ms (Beats 83.17% submissions) ✓ Memory: 77.35 MB (Beats 53.65% submissions) Key Learning: ✓ Mastered Two Pointer optimization technique ✓ Learned efficient area calculation strategy ✓ Improved decision-making for pointer movement Learning one problem every single day 🚀 #Java #LeetCode #DSA #TwoPointers #Arrays #ProblemSolving #CodingJourney #100DaysOfCode

Day 89 of #100DaysOfLeetCode 💻✅ Solved #15. 3Sum problem in Java. Approach: • Sorted the array first • Fixed one element and used Two Pointers for the rest • Skipped duplicates to avoid repeated triplets • Adjusted pointers based on sum comparison Performance: ✓ Runtime: 30 ms (Beats 87.77% submissions) ✓ Memory: 59.02 MB (Beats 77.30% submissions) Key Learning: ✓ Mastered Two Pointer technique with sorting ✓ Learned handling duplicates efficiently ✓ Improved problem-solving for combination-based problems Learning one problem every single day 🚀 #Java #LeetCode #DSA #TwoPointers #Arrays #Sorting #ProblemSolving #CodingJourney #100DaysOfCode

Day 65 of #100DaysOfLeetCode 💻✅ Solved “Majority Frequency Group” problem in Java. Approach: • Created a frequency array of size 26 for all characters • Counted occurrences of each character in the string • For each unique frequency, counted how many characters share that frequency • Selected the frequency with the highest group size • In case of tie, chose the higher frequency • Built the result string with characters having the selected frequency Performance: ✓ Runtime: 5 ms (Beats 57.84% submissions) ✓ Memory: 44.51 MB (Beats 72.88% submissions) Key Learning: ✓ Practiced frequency grouping techniques ✓ Learned how to handle tie-breaking conditions ✓ Strengthened logic building with nested loops and conditions Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #Hashing #ProblemSolving #CodingJourney #100DaysOfCode

Solved LeetCode 17 – Letter Combinations of a Phone Number using backtracking in Java. Approach: Mapped each digit (2–9) to its corresponding characters using a simple array for O(1) access. Then used backtracking to build combinations digit by digit. For every digit: Pick each possible character Append → explore next digit → backtrack Key idea: Treat it like a tree of choices, where each level represents a digit and branches represent possible letters. Key learnings: Backtracking = build → explore → undo StringBuilder helps avoid unnecessary string creation Problems like this are about systematic exploration of choices Time Complexity: O(4^n * n) Space Complexity: O(n) recursion stack + output Consistent DSA practice is strengthening pattern recognition day by day. #Java #DSA #Backtracking #LeetCode #CodingInterview #SoftwareEngineering

Day 72 of #100DaysOfLeetCode 💻✅ Solved #3866 “First Unique Even Element” problem in Java. Approach: • Traversed the array to find even numbers • For each even number, counted its occurrences in the array • If the count is exactly 1, returned that number • Continued until the first unique even number is found • Returned -1 if no such number exists Performance: ✓ Runtime: 1 ms (Beats 99.36% submissions) 🚀 ✓ Memory: 45.15 MB (Beats 98.39% submissions) Key Learning: ✓ Practiced combining conditions (even + uniqueness) ✓ Improved understanding of nested loop logic ✓ Learned how to filter and validate elements efficiently Learning one problem every single day 🚀 #Java #LeetCode #DSA #Arrays #ProblemSolving #CodingJourney #100DaysOfCode

Day 76 of #100DaysOfLeetCode 💻✅ Solved #33. Search in Rotated Sorted Array problem in Java. Approach: • Applied Binary Search on rotated array • Checked which half is sorted at each step • Reduced search space based on target position Performance: ✓ Runtime: 0 ms (Beats 100.00% submissions) 🚀 ✓ Memory: 43.80 MB (Beats 70.96% submissions) Key Learning: ✓ Mastered searching in rotated sorted arrays ✓ Improved Binary Search decision-making ✓ Learned efficient handling of edge cases Learning one problem every single day 🚀 #Java #LeetCode #DSA #BinarySearch #Arrays #ProblemSolving #CodingJourney #100DaysOfCode