Python Program for Coin Change

• Difficulty Level : Hard
• Last Updated : 19 Jan, 2018

Given a value N, if we want to make change for N cents, and we have infinite supply of each of S = { S1, S2, .. , Sm} valued coins, how many ways can we make the change? The order of coins doesn\’t matter.

For example, for N = 4 and S = {1,2,3}, there are four solutions: {1,1,1,1},{1,1,2},{2,2},{1,3}. So output should be 4. For N = 10 and S = {2, 5, 3, 6}, there are five solutions: {2,2,2,2,2}, {2,2,3,3}, {2,2,6}, {2,3,5} and {5,5}. So the output should be 5.

Python

 # Dynamic Programming Python implementation of Coin # Change problemdef count(S, m, n):    # We need n+1 rows as the table is constructed     # in bottom up manner using the base case 0 value    # case (n = 0)    table = [[0 for x in range(m)] for x in range(n+1)]      # Fill the entries for 0 value case (n = 0)    for i in range(m):        table[i] = 1      # Fill rest of the table entries in bottom up manner    for i in range(1, n+1):        for j in range(m):              # Count of solutions including S[j]            x = table[i - S[j]][j] if i-S[j] >= 0 else 0              # Count of solutions excluding S[j]            y = table[i][j-1] if j >= 1 else 0              # total count            table[i][j] = x + y      return table[n][m-1]  # Driver program to test above functionarr = [1, 2, 3]m = len(arr)n = 4print(count(arr, m, n))  # This code is contributed by Bhavya Jain

Python

 # Dynamic Programming Python implementation of Coin # Change problemdef count(S, m, n):      # table[i] will be storing the number of solutions for    # value i. We need n+1 rows as the table is constructed    # in bottom up manner using the base case (n = 0)    # Initialize all table values as 0    table = [0 for k in range(n+1)]      # Base case (If given value is 0)    table = 1      # Pick all coins one by one and update the table[] values    # after the index greater than or equal to the value of the    # picked coin    for i in range(0,m):        for j in range(S[i],n+1):            table[j] += table[j-S[i]]      return table[n]  # Driver program to test above functionarr = [1, 2, 3]m = len(arr)n = 4x = count(arr, m, n)print (x)  # This code is contributed by Afzal Ansari

Please refer complete article on Dynamic Programming | Set 7 (Coin Change) for more details!

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