JavaAlgorithms/DynamicProgramming/MinimumSumPartition.java
tribbleofjim e8a4628c96
Update DynamicProgramming/MinimumSumPartition.java
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>
2020-09-06 16:53:25 +08:00

96 lines
2.3 KiB
Java

package DynamicProgramming;
// Partition a set into two subsets such that the difference of subset sums is minimum
/*
Input: arr[] = {1, 6, 11, 5}
Output: 1
Explanation:
Subset1 = {1, 5, 6}, sum of Subset1 = 12
Subset2 = {11}, sum of Subset2 = 11
Input: arr[] = {36, 7, 46, 40}
Output: 23
Explanation:
Subset1 = {7, 46} ; sum of Subset1 = 53
Subset2 = {36, 40} ; sum of Subset2 = 76
*/
import java.util.*;
import java.lang.*;
import java.io.*;
public class MinimumSumPartition
{
public static int subSet(int[] arr) {
int n = arr.length;
int sum = getSum(arr);
boolean[][] dp = new boolean[n + 1][sum + 1];
for (int i = 0; i <= n; i++) {
dp[i][0] = true;
}
for (int j = 0; j <= sum; j++) {
dp[0][j] = false;
}
//fill dp array
for(int i = 1; i <= n; i++){
for(int j = 1; j <= sum; j++){
if(arr[i-1] < j){
dp[i][j] = dp[i-1][j - arr[i-1]] || dp[i-1][j];
}
else if(arr[i-1] == j){
dp[i][j] = true;
}
else{
dp[i][j] = dp[i-1][j];
}
}
}
// fill the index array
int index[] = new int[sum];
int p = 0;
for(int i = 0; i <= sum / 2; i++){
if(dp[n][i]){
index[p++] = i;
}
}
return getMin(index, sum);
}
/**
* Calculate sum of array elements
*
* @param arr the array
* @return sum of given array
*/
public static int getSum(int[] arr) {
int sum = 0;
for (int temp : arr) {
sum += temp;
}
return sum;
}
public static int getMin(int[] arr, int sum) {
if (arr.length == 0) {
return 0;
}
int min = Integer.MAX_VALUE;
for (int temp : arr) {
min = Math.min(min, sum - 2 * temp);
}
return min;
}
public static void main(String args[]){
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int arr[] = new int[n];
for(int i = 0 ; i<n; i++){
arr[i] = in.nextInt();
}
System.out.println(subSet(arr));
}
}