


Given 2 bits, determine the result of the given binary
operation (AND or OR).
Reading inputs:
Reading from standard input:
Scanner sc = new Scanner(System.in);

Type 1: read N operations
N = sc.nextInt();
for (int i = 0; i < N; i++) {
operator = sc.next();
firstBit = sc.nextInt();
secondBit = sc.nextInt();
// process the result accordingly
}
Problem 1: HelloWorld
2

Type 2: read until special character ‘0’
while (true) {
operator = sc.next();
if (operator.equals(specialCharacter))
break;
bit1 = sc.nextInt();
bit2 = sc.nextInt();
// process the result accordingly
}

Type 3: read until end of file
while (sc.hasNext()) {
operator = sc.next();
bit1 = sc.nextInt();
bit2 = sc.nextInt();
// process the result accordingly
}
Problem 1: HelloWorld
3

A string S[0…n-1] is palindrome iff
◦ S[0] = S[n-1], S[1] = S[n-2], S[2] = S[n-3], …
◦ i.e. S[i]=S[n-1-i] for every i.
for (int i = 0; i < len; i++) {
if (s.charAt(i) != t.charAt(len - i - 1)) {
palindrome = false; break;
}
}
Alternatively, just reverse the second string and use the
equals() method

Use compareTo( ) method (can be used for
objects in Java).
When comparing two strings, a and b:
int comparisonResult = a.compareTo(b);

The method returns:
 0 if they are lexicographically same
 >= 1 if a is lexicographically ‘larger’ than b
 <= -1 if a is lexicographically ‘smaller’ than b
ADDITIONAL SLIDES

Suppose your java classname is Test, the input filename
is “test.in” and the correct output filename is “test.out”

Run your program and store your program’s output in
“test.tmp”

java Test < test.in > test.tmp

Compare test.out and test.tmp.

diff test.tmp test.out

If diff doesn’t produce any output, then “test.tmp”
and “test.out” are exactly the same (your
program produces the correct output)
8

java Test < test1.in > test1.tmp

diff test1.tmp test1.out

java Test < test2.in > test2.tmp

diff test2.tmp test2.out

java Test < test3.in > test3.tmp

diff test3.tmp test3.out

java Test < test4.in > test4.tmp

diff test4.tmp test4.out

... ... ... ... ... ...
9
for i in {1 .. 8}
do
java Test < test$i.in > test$i.tmp
diff test$i.tmp test$i.out
done
//YEAY
10
END OF FILE