-
Notifications
You must be signed in to change notification settings - Fork 0
/
Unbounded Knapsack.java
109 lines (94 loc) · 2.62 KB
/
Unbounded Knapsack.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
class Solution{
static int knapSack(int N, int W, int val[], int wt[])
{
// code here
int dp[][]=new int[N][W+1];
for(int row[]:dp)
{
Arrays.fill(row,-1);
}
// return Knapsackrecursive(N-1,W,val,wt);
// return KnapsackMemoization(N-1,W,val,wt,dp);
// return KnapsackDP(N,W,val,wt);
return KnapsackDPOptimized(N,W,val,wt);
}
//Recursive Approach
public static int Knapsackrecursive(int N,int W,int val[],int wt[])
{
if(N==0)
{
return ((int)(W/wt[0]))*val[0];
}
int nottake=Knapsackrecursive(N-1,W,val,wt);
int take=0;
if(W>=wt[N])
{
take=val[N]+Knapsackrecursive(N,W-wt[N],val,wt);
}
return Math.max(take,nottake);
}
//Memoization Approach
public static int KnapsackMemoization(int N,int W,int val[],int wt[],int dp[][])
{
if(N==0)
{
return ((int)(W/wt[0]))*val[0];
}
if(dp[N][W]!=-1) return dp[N][W];
int nottake=KnapsackMemoization(N-1,W,val,wt,dp);
int take=0;
if(W>=wt[N])
{
take=val[N]+KnapsackMemoization(N,W-wt[N],val,wt,dp);
}
return dp[N][W]=Math.max(take,nottake);
}
//DP Approach
public static int KnapsackDP(int N,int W,int val[],int wt[])
{
int dp[][]=new int[N][W+1];
for(int i=0;i<=W;i++)
{
dp[0][i]=((int)(i/wt[0]))*val[0];
}
for(int i=1;i<N;i++)
{
for(int j=0;j<=W;j++)
{
int nottake=dp[i-1][j];
int take=0;
if(j>=wt[i])
{
take=val[i]+dp[i][j-wt[i]];
}
dp[i][j]=Math.max(take,nottake);
}
}
return dp[N-1][W];
}
//Space Optimized DP
public static int KnapsackDPOptimized(int N,int W,int val[],int wt[])
{
int dp[]=new int[W+1];
for(int i=0;i<=W;i++)
{
dp[i]=((int)(i/wt[0]))*val[0];
}
for(int i=1;i<N;i++)
{
int curr[]=new int[W+1];
for(int j=0;j<=W;j++)
{
int nottake=dp[j];
int take=0;
if(j>=wt[i])
{
take=val[i]+curr[j-wt[i]];
}
curr[j]=Math.max(take,nottake);
}
dp=curr;
}
return dp[W];
}
}