osshu320 / dynamic-programming-questions-by-aditya-verma

Aditya Verma (Youtube) DP Playlist Codes/Solutions.

Dynamic-Programming-Questions-by-Aditya-Verma

Codes of all questions covered by Aditya Verma in his Dynamic Programming Lectures
(Codes are tested on gfg / leetcode and are in the order of videos)
Note: Click on title of question to go to the page of code

• 0/1 Knapsack
  • Knapsack Recursive
    • Video Link
  • Knapsack Memoization
    • Video Link
  • Knapsack Bottom-up
    • Video Link
  • Subset Sum Problem
    • Video Link
  • Equal Sum Partition Problem
    • Video Link
  • Count of Subsets Sum with a Given Sum
    • Video Link
  • Min Subset Sum Difference
    • Video Link
  • Count of Subsets with given diff
    • Video Link
  • Target Sum - Specific to leetcode problem
    • Video Link
• Unbounded Knapsack
  • Rod Cutting Problem
    • Video Link
  • Coin Change - I: max number of ways
    • Video Link
  • Coin Change - II: min number of coins
    • Video Link
• Longest Common Subsequence (LCS)
  • LCS Recursive
    • Video Link
  • LCS Memoization
    • Video Link
  • LCS Bottom - Up DP
    • Video Link
  • Longest Common Substring
    • Video Link
  • Print LCS
    • Video Link
  • Shortest Common Supersequence (SCS)
    • Video Link
  • Min # of insertion and deletion to convert a to b
    • Video Link
  • Longest Pallindromic Subsquence (LPS)
    • Video Link
  • Min Number of deletions in string to make it pallindrome
    • Video Link
  • Print SCS
    • Video Link
  • Longest Repeating Subsequence
    • Video Link
  • Sequence Pattern Matching
    • Video Link
  • Min number of insertion in a string to make string pallindrome
    • Video Link
• Matrix Chain Multiplication (MCM)
  • MCM Recursive
    • Video Link
  • MCM Memoization
    • Video Link
  • Pallindrome Partitioning Recursive
    • Video Link
  • Pallindrome Partitioning Memoization
    • Video Link
  • Pallindrome Partitioning Optimization -> Still Giving TLE on GFG(Will Update if found better)
    • Video Link
    • To Solve these problem on GFG Click Here.
  • Evaluate Expression to true Recursive
    • Video Link
  • Evaluate Expression to true Memoization: Using Map -> Giving TLE on GFG (Will Update if found better)
    • Video Link
    • To Solve these problem on GFG Click Here.
  • Evaluate Expression to true Memoization: Using 3d Array
    • Video Link
  • Scramble String Recursive
    • Video Link
  • Scramble String Memoization
    • Video Link
    • To Solve these problem on leetcode Click Here.
  • Egg Dropping Problem Recursive
    • Video Link
  • Egg Dropping Problem Memoization
    • Video Link
  • Egg Dropping Problem Memoization Optimization - As suggested in lectures
    • Video Link
    • To Solve these problem on GFG Click Here.
  • Egg Dropping Problem Optimization Using Concept of Binary Search - Accepted on Leetcode (Credits: Comment below video)
    • To Solve these problem on leetcode Click Here.
• DP on Trees (Direct Solutions to leetcode / gfg problems)
  • Diameter of Binary Tree
    • Video Link
    • To Solve these problem on leetcode Click Here.
  • Maximum path sum (from any node to any node)
    • Video Link
    • To Solve these problem on leetcode Click Here.
  • Maximum path sum from leaf to leaf
    • Video Link
    • To Solve these problem on GFG Click Here.

dynamic-programming-questions-by-aditya-verma's Issues

TestCase Failing for above code

for : count_of_subsets_with_given_sum.cpp (https://github.com/shubhamchemate003/Dynamic-Programming-Questions-by-Aditya-Verma/blob/main/count_of_subsets_with_given_sum.cpp)

is failing for

n=10 
sum=31
arr[] = 9 7 0 3 9 8 6 5 7 6

Working Code :

for(int i=0;i<=sum;i++)
          t[0][i]=0;
            
 t[0][0]=1;
        
        for(int i=1;i<=n;i++){
            for(int j=0;j<=sum;j++){ // j=0 works for above case though I was not able to find the exact reason for same
                if(arr[i-1]<=j)
                    t[i][j]=t[i-1][j] + t[i-1][j-arr[i-1]];
                else
                    t[i][j]=t[i-1][j]%m;
            }
        }

Palindrome Partitioning Memoization

Hey, this repo you have made has helped me a lot, because I get the logic but when it comes to coding it, it sometimes feels difficult, so thank you for making this amazing repo 🙌🙌.

In this -> https://github.com/shubhamchemate003/Dynamic-Programming-Questions-by-Aditya-Verma/blob/main/pallindrome_partitioning_memoization.cpp

and in this too -> https://github.com/shubhamchemate003/Dynamic-Programming-Questions-by-Aditya-Verma/blob/main/pallindrome_partitioning_memoized_optimization.cpp

just pass the string with reference(&) in both the function ( isPallindrome and Solve) and it will not give TLE .
Just wanted to help, because I think there would be a lot of people like me who are getting help through this repo.

code :

bool isPallindrome(string &X, int i, int j) {
	while (i <= j) {
		if (X[i] != X[j])
			return false;
		i++, j--;
	}

	return true;
}

int Solve(string &X, int i, int j) {
	if (i >= j || isPallindrome(X, i, j)) {
		t[i][j] = 0;
		return 0;
	}

	if (t[i][j] != -1)
		return t[i][j];

	int ans = INT_MAX;
	for (int k = i; k < j; k++) {
		int temp_ans = Solve(X, i, k) + Solve(X, k + 1, j) + 1;
		ans = min(ans, temp_ans);
	}

	return t[i][j] = ans;
} 

Change the knapsack_top_down_dp to bottom_up_dp or Tabulation method

knapsack_top_down_dp is actually not top down , memoization is another name of top down . This is Tabulation method known as bottom up can you please change the name of the file ?

run time error by using memoisation in 0-1 knapsack problem

https://practice.geeksforgeeks.org/problems/0-1-knapsack-problem0945/1#

int knapSack(int W, int wt[], int val[], int n) 
    {  
       int t[n+1][w+1];
   memset(t,-1,sizeof(t));
      if(n==0 || w==0){return 0;}
       if(t[n][w]!=-1){
       return t[n][w];}
       else{
       if(w>=wt[n-1])
          t[n][w]=max(val[n-1]+knapSack(w-wt[n-1],wt,val,n-1),knapSack(w,wt,val,n-1));
       else
           t[n][w]=knapSack(w,wt,val,n-1);
       return t[n][w];
    }}};