#include<stdio.h>
int max(int a,int b)
{
if(a>b)
return a;
else
return b;
}
void knapsack(int m,int n,int w[],int p[])
{
int v[10][10],x[10],i,j;
for(i=0;i<=n;i++)
{
for(j=0;j<=m;j++)
{
if(j==0||i==0)
v[i][j]=0;
if(j-w[i]<0)
v[i][j]=v[i-1][j];
else
v[i][j]=max(v[i-1][j],v[i-1][j-w[i]]+p[i]);
}
}
for(i=0;i<=n;i++)
{
for(j=0;j<=m;j++)
printf("%d\t",v[i][j]);
printf("\n");
}
printf("THE OPTIMAL SOLUTION IS:%d",v[n][m]);
for(i=1;i<=n;i++)
x[i]=0;
i=n;
j=m;
while(i>0 && j>0)
{
if(v[i][j]!=v[i-1][j])
{
x[i]=1;
j=j-w[i];
}
i--;
}
printf("THE OPTIMAL SET OF WEIGHTS IS:");
for(i=1;i<=n;i++)
if(x[i]==1)
printf("%d\t",i);
printf("\n");
}
int main()
{
int w[10],p[10],i,m,n;
printf("ENTER THE NUMBER OF ITEMS:");
scanf("%d",&n);
printf("ENTER THE WEIGHTS OF THE ITEMS:");
for(i=1;i<=n;i++)
scanf("%d",&w[i]);
printf("ENTER THE PROFITS OF THE ITEMS:");
for(i=1;i<=n;i++)
scanf("%d",&p[i]);
printf("ENTER THE CAPACITY OF KNAPSACK:");
scanf("%d",&m);
knapsack(m,n,w,p);
return 0;
}
SAMPLE OUTPUT:
chaitanya@chaitanya-laptop:~/Desktop/My prog$ ./a.out
ENTER THE NUMBER OF ITEMS:5
ENTER THE WEIGHTS OF THE ITEMS:3
2
1
2
3
ENTER THE PROFITS OF THE ITEMS:2
3
2
3
2
ENTER THE CAPACITY OF KNAPSACK: 8
0 -72 -1080992920 -72 0 1 -1080993280 0 13403040
0 -72 -1080992920 2 0 1 -70 2 13403040
0 -72 3 2 0 5 3 4 13403040
0 2 3 5 4 5 7 5 13403040
0 2 3 5 6 8 7 8 13403040
0 2 3 5 6 8 7 8 13403040
THE OPTIMAL SOLUTION IS:13403040
THE OPTIMAL SET OF WEIGHTS IS:
Note: The same program produces a legitimate output for the same input when compiled in the "Turbo C" compiler.
So that leads me to believe that i am not adhering to C standards. Is that so?
When you initialize w you are using 1-based indexing:
for(i=1;i<=n;i++)
scanf("%d",&w[i]);
But when you access it, you are using 0-based indexing.
for(i=0;i<=n;i++)
{
for(j=0;j<=m;j++)
{
if(j==0||i==0)
v[i][j]=0;
if(j-w[i]<0) // This line accesses w[0] when i is 0. Missing an else?
v[i][j]=v[i-1][j];
else
v[i][j]=max(v[i-1][j],v[i-1][j-w[i]]+p[i]);
}
}
In C arrays use 0-based indexing. Change your code to use 0-based indexing consistently.
Also, you should check the return value of scanf
otherwise invalid input will give strange results instead of an error.
for (i=0; i < n; i++) {
if (scanf("%d", &w[i]) != 1) {
return EXIT_FAILURE; // Handle the error appropriately.
}
}