-1

I am trying to solve coin change problem using dynamic programming approach. What i have done is used a less space consuming one. Here goes my code:

 #include <cmath>
 #include <cstdio>
 #include <vector>
 #include <iostream>
 #include <algorithm>
 #include <cstring>
 using namespace std;
 int coinchange(int S[],int m,int n){
 long long table[n+1];

 // Initialize all table values as 0
memset(table, 0, sizeof(table));

// Base case (If given value is 0)
table[0] = 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(int i=0; i<m; i++)
    for(int j=S[i]; j<=n; j++)
        table[j] += table[j-S[i]];

return table[n];
}

int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */   
int nn,mm,ar[250];
cin>>mm>>nn;
for(int i=0;i<nn;i++)
    cin>>ar[i];
long long c=coinchange(ar,nn,mm);
cout<<c;
return 0;
}

it is showing wrong answer for the following test case: input: 250 24 41 34 46 9 37 32 42 21 7 13 1 24 3 43 2 23 8 45 19 30 29 18 35 11 expected output: 15685693751

Sarin Nanda
  • 35
  • 1
  • 7
  • Please consider accepting the answer if it resolved your problem. If not please let me know. – Naman Jul 15 '15 at 23:02

2 Answers2

0

The code is correct. You are just returning an 'int' instead of 'long long' from your coinchange function. Everything else is correct. Try to debug your code by printing the intermediate values. It helps you in understanding your code better for future.

Naman
  • 2,569
  • 4
  • 27
  • 44
0

Because you return the value as "int" data type,which causes "signed integer overflow: 1656720088 + 569919779 cannot be represented in type int" ERROR.

Try changing the return data type of the function and the data type of the DP table you used to store the result as "uint64_t".

Do the following changes; 1.Change the data type of your array that stores the result as "uint64_t". 2.Change the return data type of the function as "uint64_t".

uint64_t ways(int n, vector<int> coins) {
    
    uint64_t t[n+1];
for(int i=0;i<=n;i++)
    t[i]=0;
t[0]=1.0;
for(int i=0;i<coins.size();i++)
{
    for(int j=coins[i];j<=n;j++)
    {
       // if(j>=coins[i])
        t[j]+=t[j-coins[i]];
    }
}
return t[n];
}

2.Change the data type of variable that recieves the returned value from a particular function as "uint64_t".

uint64_t res = ways(n, coins);
Deva Dharshini
  • 1