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Java - Algorithms

Bubble Sort, the rules as follows:
1. Compare two players
2. If the one on the left is taller, swap them
3. Move one position right.
4.Continue down the line this way until you reach the right end.
class ArrayBub{
private double[] a; // ref to array a
private int nElems; // number of data items

public void bubbleSort(){
int out, in;

for(out=nElems -1; out > 1; out--)
 for(in =0 ; in<out;i++){
 if(a[in]> a[in+1])
  swap(in, in+1);
}//end bubbleSort
}

private void swap(int one ,int two){
 double temp = a[one];
a[one] = a[two];
a[two]=temp;
}

Efficiency of the Bubble Sort:
Runs:O(N2) time
(N-1) + (N-2) + ... + 1=N*(N-1)/2
Number of swaps O(N2)

Selection Sort: The shortest player is then swapped with the player on the left end of the line. at position 0. Now the leftmost player is sorted, and won't need to be moved again. Notice that in this algorithm the sorted player accumulated on the left, while in the bubble sort they accumulated on the right.

public void selectionSort(){
int out, in;
int nElems;
int min;
for(out; out < nElems; out++)
  min = out;
  for(in=out+1;in<nelems;in++)
  if(a[min]<a[in]
       min = in;
  swap(out,min);
}

Runs:O(N2) time
Number of swaps O(N)

Insertion-Sort:
pulbic static void insertionSort(]{
//out : current
int in,out;
//index from the second character in a the current character to be inserted start comparing with cell left
for(out = 1; out <nElems; out++)
{
//remove marked item
double temp = a[out];
//start shifts at out
in = out;
//until one is smaller
while(in > 0 && a[in-l] >=temp) {
a[in] = a[in-1];
--in;
}
//the proper place for temp
a[in] = temp;
} //end for

} //end insertionSort()

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