merge java code example

Example 1: how to add two map values in java

//map 1
HashMap<Integer, String> map1 = new HashMap<>();
 
map1.put(1, "A");
map1.put(2, "B");
map1.put(3, "C");
map1.put(5, "E");
 
//map 2
HashMap<Integer, String> map2 = new HashMap<>();
 
map2.put(1, "G");   //It will replace the value 'A'
map2.put(2, "B");
map2.put(3, "C");
map2.put(4, "D");   //A new pair to be added
 
//Merge maps
map1.putAll(map2);
 
System.out.println(map1);

Example 2: how to write a merge sort array method ni java

public static void mergeSort(int[] a, int n) {
    if (n < 2) {
        return;
    }
    int mid = n / 2;
    int[] l = new int[mid];
    int[] r = new int[n - mid];
 
    for (int i = 0; i < mid; i++) {
        l[i] = a[i];
    }
    for (int i = mid; i < n; i++) {
        r[i - mid] = a[i];
    }
    mergeSort(l, mid);
    mergeSort(r, n - mid);
 
    merge(a, l, r, mid, n - mid);
}

Example 3: how to write a merge sort array method ni java

public static void merge(
  int[] a, int[] l, int[] r, int left, int right) {
  
    int i = 0, j = 0, k = 0;
    while (i < left && j < right) {
        if (l[i] <= r[j]) {
            a[k++] = l[i++];
        }
        else {
            a[k++] = r[j++];
        }
    }
    while (i < left) {
        a[k++] = l[i++];
    }
    while (j < right) {
        a[k++] = r[j++];
    }
}