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MergeSort.java
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MergeSort.java
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public class MergeSort {
public static void conquer(int arr[], int si, int mid, int ei) {
int merged[] = new int[ei - si + 1];
int idx1 = si;
int idx2 = mid + 1;
int x = 0;
while (idx1 <= mid && idx2 <= ei) {
if (arr[idx1] <= arr[idx2]) {
merged[x++] = arr[idx1++];
} else {
merged[x++] = arr[idx2++];
}
}
while (idx1 <= mid) {
merged[x++] = arr[idx1++];
}
while (idx2 <= ei) {
merged[x++] = arr[idx2++];
}
for (int i = 0, j = si; i < merged.length; i++, j++) {
arr[j] = merged[i];
}
}
public static void divide(int arr[], int si, int ei) {
if (si >= ei) {
return;
}
int mid = (si + ei) / 2;
divide(arr, si, mid);
divide(arr, mid + 1, ei);
conquer(arr, si, mid, ei);
}
public static void main(String[] args) {
int arr[] = { 5, 1, 2, 1, 7, 3 };
int n = arr.length;
divide(arr, 0, n - 1);
// print
for (int i = 0; i < n; i++) {
System.out.print(arr[i] + " ");
}
System.out.println();
}
}