Given an array of integers. Count the number of subsets whose sum of elements equals to sum.
Example 1:
int[] a = {2, 3, 5, 6, 8, 10} sum = 10 Output: 3 Explanation: Possible choices are {2,8} , {2,3,5}, {10}
Example 2:
int[] a = {1, 2, 3, 3} sum = 6 Output: 3 Explanation: Possible choices are {1,2,3} , {1,2,3}, {3,3}Solution:
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import java.util.Arrays;
class CountOfSubsetsOfGivenSum {
static int countSubsets(int[] a, int k) {
int[][] dp = new int[a.length + 1][k + 1];
int res = 0;
for (int i = 0; i < dp.length; i++) {
dp[i][0] = 1;
}
for (int i = 1; i <= a.length; i++) {
for (int j = 1; j <= k; j++) {
if (a[i - 1] <= j) {
dp[i][j] = dp[i - 1][j - a[i - 1]] + dp[i - 1][j];
} else {
dp[i][j] = dp[i - 1][j];
}
}
}
for (int i = 0; i < dp.length; i++) {
System.out.println(Arrays.toString(dp[i]));
}
return dp[a.length][k];
}
public static void main(String[] args) {
// int[] a = {1, 2, 3, 3};
// int k = 6;
// int[] a = {2,3,5,6,8,10};
// int k = 10;
int[] a = {5969561,8742425,2513572,3352059,9084275,2194427,1017540,2324577,6810719,8936380,7868365,2755770,9954463,9912280,4713511};
int sum = 0;
int max = 0;
for(int i : a) {
sum += i;
max = Math.max(max, i);
}
sum = sum / 4;
int k = sum;
System.out.println(countSubsets(a, k));
}
}