Merge pull request #193 from erdenezul/coin_change_problem

add coin change problem

dynamic_programming/coin_change.py

@@ -0,0 +1,25 @@
+"""
+You have m types of coins available in infinite quantities
+where the value of each coins is given in the array S=[S0,... Sm-1]
+Can you determine number of ways of making change for n units using
+the given types of coins?
+https://www.hackerrank.com/challenges/coin-change/problem
+"""
+def dp_count(S, m, n):
+    table = [0] * (n + 1)
+
+    # Base case (If given value is 0)
+    table[0] = 1
+
+    # Pick all coins one by one and update 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]
+
+if __name__ == '__main__':
+    print dp_count([1, 2, 3], 3, 4)  # answer 4
+    print dp_count([2, 5, 3, 6], 4, 10)  # answer 5