I followed a tutorial on mergesort algoorithm in java and it displayed 0000002468 as result.
I gave input of number from 1,2,3…9,0.
It was supposed to sort in ascending order.
I double checked with the tutorial also and found nothing wrong.
I can’t solve it myself since i didn’t really understand.
Tutorial is by BroCode btw.
Code:
class m{
public static void main(String[]args){
int array[] = {8,4,5,3,2,7,1,9,0,6};
mergeSort(array);
for(int i =0;i<array.length;i++){
System.out.print(array[i] + "");
}
}
private static void mergeSort(int[]array){
int length = array.length;
if(length<=1)return;//base case
int middle = length/2;
int leftArray[] = new int[middle];
int rightArray[] = new int[length-middle];
int i=0;//left array
int j = 0;//right array
for(;i<length;i++){
if(i<middle){
leftArray[i] = array[i];
}else{
rightArray[j] = array[i];
}
}mergeSort(leftArray);
mergeSort(rightArray);
merge(leftArray,rightArray,array);
}
private static void merge(int[]leftArray,int[]rightArray,int[]array){
int leftSize = array.length/2;
int rightSize = array.length-leftSize;
int i=0,l=0,r=0;
// check conditions for merging
while(l<leftSize && r<rightSize){
if(leftArray[l]<rightArray[r]){
array[i] = leftArray[l];
i++;
l++;
}else{
array[i] = rightArray[r];
i++;
r++;
}
}
while(l<leftSize){
array[i] = leftArray[l];
i++;
l++;
}
while(r<rightSize){
array[i] = rightArray[r];
i++;
r++;
}
}
}
>Solution :
You forgot to increment your j
index while breaking down the original array into 2.
else{
rightArray[j++] = array[i];
}
In your code, you are just setting and replacing again and again the first element of the array, rightArray
.