Greedy Algorithm
A Greedy algorithm is one of the problem-solving methods which takes optimum solution in each mistreat .
The Greedy algorithm attempts to take the best in each step and it does n’t care about the overall consequence.
Reading: Greedy Algorithm | Minimum coin change problem greedy | When does the greedy algorithm fail
Greedy Approach – “ living in the stage. Do n’t overthink about the future ” .
Let ‘s discus avid overture with minimum mint change trouble .
Minimum Coin Change Problem
Given a fit of coins and a prize, we have to find the minimum count of coins which satisfies the value .
Example
coins [ ] = { 5,10,20,25 }
prize = 50
Possible Solutions
{ mint * count }
{ 5 * 10 } = 50 [ 10 coins ]
{ 5 * 8 + 10 * 1 } = 50 [ 9 coins ] goes on .
{ 10 * 5 } = 50 [ 5 coins ]
{ 20 * 2 + 10 * 1 } = 50 [ 3 coins ]
{ 20 * 2 + 5 * 2 } = 50 [ 4 coins ]
{ 25 * 2 } = 50 [ 2 coins ]
etc etc
Best Solution
Two 25 rupees. entire coins two .
25 * 2 = 50
Minimum Coin Change Problem Algorithm
1. Get coin array and a value .
2. Make sure that the array is sorted .
3. Take coin [ i ] angstrom much we can .
4. Increment the count .
5. If solution found ,
& nbspbreak it .
6. differently ,
follow step 3 with the adjacent mint. coin [ i+1 ] .
4. finally, print the count .
Example
coin [ ] = { 25,20,10,5 }
value = 50
Take coin [ 0 ] twice. ( 25+25 = 50 ) .
sum coins = 2 ( 25+25 )
Example
coin [ ] = { 25,20,10,5 }
value = 70
Take coin [ 0 ] twice. ( 25+25 = 50 ) .
If we take mint [ 0 ] one more time, the end consequence will exceed the given value. So, change the future mint .
Take coin [ 1 ] once. ( 50 + 20 = 70 ) .
entire coins needed = 3 ( 25+25+20 ) .
In this approach, we are not bothering about the overall result .
We equitable pick the best option in each tone and hoping that it might produce the best overall consequence .
therefore, this method acting called as the avaricious access .
Implementation of minimum coin change problem
example
# include# define soap 100 //arr - will have tilt of necessitate coins int ans[max]; int findMinCoins( int coins[], int size, int value) { int i, count = 0; for(i = 0; i < size; i ++ ) { //take as much from coins [ i ] while(value > = coins[i]) { //after taking the coin, reduce the respect . value -= coins[i]; ans[count] = coins[i]; count ++; } if(value == 0) fracture; } return key count; } int independent() { int coins[] = { 25, 20, 10, 5}; int value = 105, i; //find the size of the coins array int size = sizeof(coins) / sizeof(coins[ 0]); int MinCount = findMinCoins(coins,size,value); printf( `` sum Coins Needed = % five hundred \n ``,MinCount); printf( `` Coins are : \t ``); for(i = 0; i < MinCount; i ++) printf( `` % vitamin d ``, ans[i]); return 0; }
When does the above greedy algorithm fail?
Let 's take this scenario .
coins [ ] = { 25,20,10,5 }
value = 40
The avid solution will be 25+10+5 [ 3 coins ] .
But the optimum solution will be 20+20 [ 2 coins ] .
so, we ca n't guarantee that the avaricious algorithm always produces the overall best leave .
Read more: How to Make a Coin Bezel Necklace – Easy!
Leave a Comment