### Data structure program to knapsack using dynamic programming

/* program to knapsack using dynamic programming*/
#include<stdio.h>
#define MAX(a,b) a>b?a:b
int v[20][20];
struct KNAP
{
char item[15];
int value;
int weight;
}bag[20];
void knap(int n,int W)
{
int i,j;
int t1,t2;
for(i=0;i<=n;i++)
v[i][0]=0; //making first col as zero
for(i=0;i<=W;i++)
v[0][i]=0; //making first row as zero
for(i=1;i<=n;i++)
for(j=1;j<=W;j++)
{
if(j<bag[i].weight)
v[i][j]=v[i-1][j];
else
{
t1= v[i-1][j];
t2=v[i-1][j-bag[i].weight]+bag[i].value;
v[i][j]=MAX(t1,t2);
}
}
printf("\n\n\t\tVALUE MATRIX\n\n\t");
for(i=0;i<=n;i++,printf("\n\t"))
for(j=0;j<=W;j++,printf("\t"))
printf("%d",v[i][j]);
}
void finditem(int n,int W)
{
int i,j;
printf("\n\n\t\tITEM IN THE BAG\n\n");
for(i=n,j=W;i!=0 && j!=0;i--)
{
if(v[i][j]!=v[i-1][j])
{
printf("\t%s",bag[i].item);
j=j-bag[i].weight;
}
}
}
void main()
{
int n,i,j,W;
clrscr();
printf("\n\n\t\tKNAPSACK PROBLEM USING DYNAMIC PROGRAMMING\n\n");
printf("\n\tEnter No. of Items : ");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
fflush(stdin);
printf("\n\tEnter the Item %d name : ",i);
scanf("%s",bag[i].item);
printf("\nEnter the Weight & Valus of %s : ",bag[i].item);
scanf("%d%d",&bag[i].weight,&bag[i].value);
}
printf("\n\n\t\tEnter the Knapsack Capacity : ");
scanf("%d",&W);
clrscr();
printf("\n\n\t\tINITIAL STATE OF THE PROBLEM\n");
printf("\n\titem\tweight\tvalue\n\n");
for(i=1;i<=n;i++)
printf("\t%s\t%d\t%d\n",bag[i].item,bag[i].weight,bag[i].value);
knap(n,W);
finditem(n,W);
getch();
}