Day-27
#SDESheetChallenge
Stacks & Queues II
✅Largest Rectangle in a Histogram: monotonic stack O(n)
✅Sliding Window Maximum: monotonic deque with k-size window O(n)
✅Implement Min Stack: a variable for cur. min. + encoded value O(1)
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Day-23
#SDESheetChallenge
Heap Done
✅Find Median from Data Stream: two heaps (min & max) balance O(log n)
✅Merge K Sorted Arrays: min heap merge O(N log k)
✅Top K Frequent Elements: frequency map + min heap O(n + m log m)
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Day-22
#SDESheetChallenge
Heap
✅Implement Max Heap: heapify Up/Down O(log n)
✅K-th Largest Element in an Array: min heap of size K O(n log k)
✅Maximum Sum Combination: max heap + sorting arrays O(n^2 + n log n + k log k)
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Day-18
#SDESheetChallenge
Backtracking
✅Permutations of a String: sort+backtrack with used character check O(n*n!)
✅N Queen: column & diagonal check+backtrack O(n!)
✅Sudoku Solver: try digits in empty cells+backtrack O(9^emptyCells)
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1. Sort end time O(nlogn)
2. Sort Arrivals & Departures & Two Pointers O(nlogn)
3. Sort by Profit + Slot Filling O(nlogn + n*m)
4. Sort by Val/Wt ratio O(nlogn)
Day-14
#SDESheetChallenge
Linked List & Arrays Done
✅Trapping Rainwater: two pointers with max boundaries O(n)
✅Remove Duplicates from sorted array: two pointers O(n)
✅Maximum Consecutive Ones: count and reset if visit 0 O(n)
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Day-13
#SDESheetChallenge
Linked List & Arrays
✅Rotate a LL: length + connect + break O(n)
✅Clone a LL with random and next pointer: insert new nodes in b/w og nodes, later separate the lists O(n)
✅3 Sum: sort + two pointers O(n²)
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