/**
* Rearrange the subarray A[p..r] in place.
*
* @param A the array to rearrange
* @param p the beginning index
* @param r the ending index
* @param t the Table to swap rows for
* @return the partition point
*/
private int partition(long[] A, int p, int r, MutableTable t) {
long x = A[p];
boolean xMissing = this.isValueMissing(p);
int i = p - 1;
int j = r + 1;
while (true) {
if (xMissing) {
j--;
do {
i++;
} while (!this.isValueMissing(i));
} else {
do {
j--;
} while (this.isValueMissing(j) || (A[j] > x));
do {
i++;
} while (!this.isValueMissing(i) && (A[i] < x));
}
if (i < j) {
if (t == null) this.swapRows(i, j);
else t.swapRows(i, j);
} else return j;
}
}
