mirror of
https://hub.njuu.cf/TheAlgorithms/C-Plus-Plus.git
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7b92e8d625
* palindrome no
a program to check if a number is palindrome or not
* updated palindrome.cpp
* updated palindrome.cpp
missing equal to operator at line no 16
* flatten_a_binary_seach_tree
This program flattens a binary search tree or in simple words, converts it into linked list in sorted form
* a prog to convert bst into linked list
A code that is used to convert a binary search tree into linked list
* created merge k sorted arrays
this program displays all the elements from the different arrays(sorted) into 1 single array(sorted).
* updated braces in some parts
* included braces in line no 58
* included braces in line 58 and 60
* created trap_rainwater.cpp
A program to calculate the maximum amount of water that can be stored between buildings.
* deleted rainwater harvesting
* deleted palindrome
* deleted merge k sorted arrays
* deleted binary search tree to linked list
* deleted binary search tree to linked list
* created min_coins_topdown.cpp
This is another version of coins exchange problem solved using top down approach
* updated the code
please take a look at it
* final changes
* updated my code
* updating DIRECTORY.md
* changed int64_t to int8_t and int16_t
* edited line 3
* changed line 3
* edited line 3 & removed line 18
* added extra space
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
90 lines
2.7 KiB
C++
90 lines
2.7 KiB
C++
/**
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* @file
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* @brief [Minimum coins](https://leetcode.com/problems/coin-change/) change problem is a problem used to find the minimum number of
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* coins required to completely reach a target amount.
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*
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* @details
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* This problem can be solved using 2 methods:
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* 1. Top down approach
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* 2. Bottom up appraoch
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* Top down approach involves a vector with all elements initialised to 0.
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* It is based on optimal substructure and overlapping subproblems.
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* Overall time complexity of coin change problem is O(n*t)
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* For example: example 1:-
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* Coins: {1,7,10}
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* Target:15
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* Therfore minimum number of coins required = 3 of denomination 1,7 and 7.
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* @author [Divyansh Kushwaha](https://github.com/webdesignbydivyansh)
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*/
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#include <iostream> // for io operations
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#include <vector> // for std::vector
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#include <cassert> // for assert
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#include <climits> // for INT_MAX
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/**
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* @namespace dynamic_programming
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* @brief Dynamic Programming algorithm
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*/
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namespace dynamic_programming {
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/**
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* @namespace mincoins_topdown
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* @brief Functions for [minimum coin exchange](https://leetcode.com/problems/coin-change/) problem
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*/
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namespace mincoins_topdown {
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/**
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* @brief This implementation is for finding minimum number of coins .
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* @param T template-type to use any kind of value
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* @param n amount to be reached
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* @param coins vector of coins
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* @param t deontes the number of coins
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* @param dp initilised to 0
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* @returns minimum number of coins
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*/
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template<typename T>
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int64_t mincoins(const T &n, const std::vector<T> &coins, const int16_t &t, std::vector<T> dp){
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if(n==0){
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return 0;
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}
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if(dp[n]!=0){
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return dp[n];
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}
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int ans=INT_MAX; //variable to store min coins
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for(int i=0;i<t;i++){
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if(n-coins[i]>=0){ //if after subtracting the current denomination is it greater than 0 or not
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int sub=mincoins(n-coins[i],coins,t,dp);
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ans=std::min(ans,sub+1);
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}
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}
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dp[n]=ans;
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return dp[n]; //returns minimum number of coins
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}
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} // namespace mincoins_topdown
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} // namespace dynamic_programming
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/**
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* @brief Test implementations
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* @returns void
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*/
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static void test() {
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// example 1: number of coins=3 and minimum coins required=3(7,7,1)
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const int64_t n1 = 15;
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const int8_t t1=3, a1=0;
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std::cout << "\nTest 1...";
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std::vector<int64_t> arr1 {1,7,10};
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std::vector<int64_t> dp1 (n1+1);
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fill(dp1.begin(),dp1.end(),a1);
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assert(dynamic_programming::mincoins_topdown::mincoins(n1, arr1, t1, dp1)==3);
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std::cout << "Passed\n";
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}
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/**
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* @brief Main function
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* @returns 0 on exit
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*/
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int main() {
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test(); // execute the test
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return 0;
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}
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