unsigned long partitionArray(int arr[], unsigned long left, unsigned long right)

{

unsigned long pivot = (rand() % (right - left + 1)) + left;

SWAP(arr[left], arr[pivot]);

unsigned long i = left + 1;

for(unsigned long j = left + 1; j <= right; ++j)

{

if(arr[j] < arr[left])

{

swap(arr[j], arr[i]);

++i;

}

}

swap(arr[i-1], arr[left]);

return i-1;

}

int RSelect(int arr[], int left, int right, int n)

{

if(left == right && left == n)

return arr[left];

int pivotIndex = partitionArray(arr, left ,right);

if(pivotIndex + 1 == n)

return arr[pivotIndex];

else if(pivotIndex + 1 > n)

return RSelect(arr, left, pivotIndex - 1, n);

else

return RSelect(arr, pivotIndex + 1, right, n);

}

{

unsigned long pivot = (rand() % (right - left + 1)) + left;

SWAP(arr[left], arr[pivot]);

unsigned long i = left + 1;

for(unsigned long j = left + 1; j <= right; ++j)

{

if(arr[j] < arr[left])

{

swap(arr[j], arr[i]);

++i;

}

}

swap(arr[i-1], arr[left]);

return i-1;

}

int RSelect(int arr[], int left, int right, int n)

{

if(left == right && left == n)

return arr[left];

int pivotIndex = partitionArray(arr, left ,right);

if(pivotIndex + 1 == n)

return arr[pivotIndex];

else if(pivotIndex + 1 > n)

return RSelect(arr, left, pivotIndex - 1, n);

else

return RSelect(arr, pivotIndex + 1, right, n);

}

## No comments:

## Post a Comment