Coin Change DP problem

Author: eatsleepcoderepeat9

coinchange.cpp

@@ -0,0 +1,51 @@
+#include<iostream>
+using namespace std;
+
+///Coin Change Problem 
+///Top Down DP
+int dp[100] = {0};
+int coinWaysTD(int amt,int coins[],int n){
+    if(amt==0){
+        dp[0] = 1;
+        return 1;
+    }
+    ///Recursive Case
+    int ans = 0;
+    
+    if(dp[amt]!=0){
+        return dp[amt];
+    }
+    for(int i=0;i<n;i++){
+        if(amt-coins[i]>=0){
+            ans += coinWaysTD(amt-coins[i],coins,n);
+        }
+    }
+    ///Store and return for the first time
+    dp[amt] = ans;
+    return ans;
+}
+
+///Bottom Up DP
+int coinWaysBU(int amt,int coins[],int n){
+    int dp[100] = {0};
+    dp[0] = 1;
+
+    for(int i=1;i<=amt;i++){
+        for(int j=0;j<n;j++){
+           if(i-coins[j]>=0){
+                dp[i] += dp[i-coins[j]];
+           }
+        }
+    }
+    return dp[amt];
+}
+
+
+int main(){
+
+    int coins[] = {1,2,3,8};
+    int amount = 3;
+    cout<<coinWaysTD(amount,coins,4)<<endl;
+    cout<<coinWaysBU(amount,coins,4)<<endl;
+return 0;
+}