/
Jewelry.java
67 lines (61 loc) · 1.75 KB
/
Jewelry.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
package tco03.onlineround4;
import java.util.Arrays;
public class Jewelry {
// Maximum sum that can be formed.
int MAX_SUM = 30000;
// Maximum no of jewelery items.
int MAX_ELEMENT = 30;
// cache for the binmoial coefficient n choose k.
long[][] comb = new long[MAX_ELEMENT + 1][MAX_ELEMENT + 1];
public long howMany(int[] values) {
Arrays.sort(values);
long ret = 0;
int groupSize = 1;
for (int i = 0; i < values.length - 1; i += groupSize) {
long[] waysBelow = getSumWays(Arrays.copyOfRange(values, 0, i));
groupSize = 1;
for (int j = i + 1; j < values.length; j++) {
if (values[j] != values[i])
break;
groupSize++;
}
for (int g = 0; g < groupSize; g++) {
long[] waysAbove = getSumWays(Arrays.copyOfRange(values, i + g + 1, values.length));
for (int s = values[i] * (g + 1); s <= MAX_SUM; s++) {
ret += (comb(groupSize, g + 1) * waysBelow[s - values[i]*(g+1)] * waysAbove[s]);
}
}
}
return ret;
}
long[] getSumWays(int[] values) {
int maxSum = sum(values);
long[] ways = new long[MAX_SUM + 1];
ways[0] = 1;
for (int i = 0; i < values.length; i++) {
for (int j = maxSum; j >= values[i]; j--) {
ways[j] += ways[j - values[i]];
}
}
return ways;
}
int sum(int[] values) {
int sum = 0;
for (int i = 0; i < values.length; i++) {
sum += values[i];
}
return sum;
}
long comb(int n, int k) {
if (comb[n][k] > 0)
return comb[n][k];
if (k == 0 || n == k)
return 1;
comb[n][k] = comb(n - 1, k - 1) + comb(n - 1, k);
return comb[n][k];
}
public static void main(String[] args) {
Jewelry j = new Jewelry();
System.out.println(j.comb(5, 2));
}
}