Greedy Algorithms

  • Last Updated : 02 Aug, 2022

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Greedy is an algorithmic paradigm that builds up a solution piece by piece, always choosing the next piece that offers the most obvious and immediate benefit. So the problems where choosing locally optimal also leads to global solution are the best fit for Greedy.

For example consider the Fractional Knapsack Problem. The local optimal strategy is to choose the item that has maximum value vs weight ratio. This strategy also leads to a globally optimal solution because we are allowed to take fractions of an item.
greedy-algorithms

Topics:

Standard Greedy Algorithms :

  1. Activity Selection Problem
  2. Egyptian Fraction
  3. Job Sequencing Problem
  4. Job Sequencing Problem (Using Disjoint Set)
  5. Job Sequencing Problem – Loss Minimization
  6. Job Selection Problem – Loss Minimization Strategy | Set 2
  7. Huffman Coding
  8. Efficient Huffman Coding for sorted input
  9. Huffman Decoding
  10. Water Connection Problem
  11. Policemen catch thieves
  12. Minimum Swaps for Bracket Balancing
  13. Fitting Shelves Problem
  14. Assign Mice to Holes

DSA-Self-Paced

Greedy Algorithms in Graphs :

  1. Kruskal’s Minimum Spanning Tree
  2. Prim’s Minimum Spanning Tree
  3. Boruvka’s Minimum Spanning Tree
  4. Reverse delete algorithm for MST
  5. Problem Solving for Minimum Spanning Trees (Kruskal’s and Prim’s)
  6. Dijkastra’s Shortest Path Algorithm
  7. Dial’s Algorithm
  8. Dijkstra’s Algorithm for Adjacency List Representation
  9. Prim’s MST for adjacency list representation
  10. Correctness of Greedy Algorithms
  11. Minimum cost to connect all cities
  12. Max Flow Problem Introduction
  13. Number of single cycle components in an undirected graph

Greedy Algorithms in Arrays :

  1. Minimum product subset of an array
  2. Maximum product subset of an array
  3. Maximize array sum after k-negations | Set 1
  4. Maximize array sum after k-negations | Set 2
  5. Maximize the sum of arr[i]*i
  6. Maximum sum of increasing order elements from n arrays
  7. Maximum sum of absolute difference of an array
  8. Maximize sum of consecutive differences in a circular array
  9. Maximum height pyramid from the given array of objects
  10. Partition into two subarrays of lengths k and (N – k) such that the difference of sums is maximum
  11. Minimum sum of product of two arrays
  12. Minimum sum by choosing minimum of pairs from array
  13. Minimum sum of absolute difference of pairs of two arrays
  14. Minimum operations to make GCD of array a multiple of k
  15. Minimum sum of absolute difference of pairs of two arrays
  16. Minimum sum of two numbers formed from digits of an array
  17. Minimum increment/decrement to make array non-Increasing
  18. Making elements of two arrays same with minimum increment/decrement
  19. Minimize sum of product of two arrays with permutation allowed
  20. Sorting array with reverse around middle
  21. Sum of Areas of Rectangles possible for an array
  22. Array element moved by k using single moves
  23. Find if k bookings possible with given arrival and departure times
  24. Lexicographically smallest array after at-most K consecutive swaps
  25. Largest lexicographic array with at-most K consecutive swaps

Greedy Algorithms in Operating Systems :

  1. First Fit algorithm in Memory Management
  2. Best Fit algorithm in Memory Management
  3. Worst Fit algorithm in Memory Management
  4. Operating System | Program for Next Fit algorithm in Memory Management
  5. Shortest Job First Scheduling
  6. Program for Shortest Job First (SJF) scheduling | Set 2 (Preemptive)
  7. Schedule jobs so that each server gets equal load
  8. Job Scheduling with two jobs allowed at a time
  9. Scheduling priority tasks in limited time and minimizing loss
  10. Program for Optimal Page Replacement Algorithm
  11. Program for Page Replacement Algorithms | Set 1 ( LRU)
  12. Program for Page Replacement Algorithms | Set 2 (FIFO)

Approximate Greedy Algorithms for NP Complete Problems :

  1. Set cover problem
  2. Bin Packing Problem
  3. Graph Coloring
  4. K-centers problem
  5. Shortest superstring problem
  6. Travelling Salesman Problem | Set 1 (Naive and Dynamic Programming)
  7. Traveling Salesman Problem | Set 2 (Approximate using MST)

Greedy Algorithms for Special Cases of DP problems :

  1. Fractional Knapsack Problem
  2. Minimum number of coins required

Misc :

  1. Split n into maximum composite numbers
  2. Maximum trains for which stoppage can be provided
  3. Buy Maximum Stocks if i stocks can be bought on i-th day
  4. Find the minimum and maximum amount to buy all N candies
  5. Maximum sum possible equal to sum of three stacks
  6. Maximum elements that can be made equal with k updates
  7. Divide cuboid into cubes such that sum of volumes is maximum
  8. Maximum number of customers that can be satisfied with given quantity
  9. Minimum Fibonacci terms with sum equal to K
  10. Divide 1 to n into two groups with minimum sum difference
  11. Minimize cash flow among friends
  12. Minimum rotations to unlock a circular lock
  13. Paper cut into minimum number of squares
  14. Minimum difference between groups of size two
  15. Minimum rooms for m events of n batches with given schedule
  16. Connect n ropes with minimum cost
  17. Minimum Cost to cut a board into squares
  18. Minimum cost to process m tasks where switching costs
  19. Minimum cost to make array size 1 by removing larger of pairs
  20. Minimum cost for acquiring all coins with k extra coins allowed with every coin
  21. Minimum time to finish all jobs with given constraints
  22. Minimum number of Platforms required for a railway/bus station
  23. Minimize the maximum difference between the heights of towers
  24. Minimum increment by k operations to make all elements equal
  25. Minimum edges to reverse to make path from a source to a destination
  26. Find minimum number of currency notes and values that sum to given amount
  27. Minimum initial vertices to traverse whole matrix with given conditions
  28. Find the Largest Cube formed by Deleting minimum Digits from a number
  29. Check if it is possible to survive on Island
  30. Largest palindromic number by permuting digits
  31. Smallest number with sum of digits as N and divisible by 10^N
  32. Find Smallest number with given number of digits and digits sum
  33. Rearrange characters in a string such that no two adjacent are same
  34. Rearrange a string so that all same characters become d distance away
  35. Print a closest string that does not contain adjacent duplicates
  36. Smallest subset with sum greater than all other elements
  37. Lexicographically largest subsequence such that every character occurs at least k times

Quick Links :

  1. Top 20 Greedy Algorithms Interview Questions
  2. ‘Practice Problems’ on Greedy Algorithms
  3. Practice Questions on Huffman Encoding
  4. ‘Quiz’ on Greedy Algorithms

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