Unit 2 Chapter 4 Stacks and Queues Code Flashcards
1
Q
priority queue
A
////////////////////////////////////////////////////////////////
class PriorityQ
{
// array in sorted order, from max at 0 to min at size-1
private int maxSize;
private long[] queArray;
private int nItems;
//-------------------------------------------------------------
public PriorityQ(int s) // constructor
{
maxSize = s;
queArray = new long[maxSize];
nItems = 0;
}
//-------------------------------------------------------------
public void insert(long item) // insert item
{
int j;
if(nItems==0) // if no items,
queArray[nItems++] = item; // insert at 0
else // if items,
{
for(j=nItems-1; j>=0; j--) // start at end,
{
if( item > queArray[j] ) // if new item larger,
queArray[j+1] = queArray[j]; // shift upward
else // if smaller,
break; // done shifting
} // end for
queArray[j+1] = item; // insert it
nItems++;
} // end else (nItems > 0)
} // end insert()
//-------------------------------------------------------------
public long remove() // remove minimum item
{ return queArray[--nItems]; }
//-------------------------------------------------------------
public long peekMin() // peek at minimum item
{ return queArray[nItems-1]; }
//-------------------------------------------------------------
public boolean isEmpty() // true if queue is empty
{ return (nItems==0); }
//-------------------------------------------------------------
public boolean isFull() // true if queue is full
{ return (nItems == maxSize); }
//-------------------------------------------------------------
} // end class PriorityQ
////////////////////////////////////////////////////////////////
class PriorityQApp
{
public static void main(String[] args)
{
PriorityQ thePQ = new PriorityQ(5);
thePQ.insert(30);
thePQ.insert(50);
thePQ.insert(10);
thePQ.insert(40);
thePQ.insert(20);
while( !thePQ.isEmpty() )
{
long item = thePQ.remove();
System.out.print(item + " "); // 10, 20, 30, 40, 50
} // end while
System.out.println("");
} // end main()
//-------------------------------------------------------------
} // end class PriorityQApp
////////////////////////////////////////////////////////////////
2
Q
stack
A
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize; // size of stack array
private long[] stackArray;
private int top; // top of stack
//--------------------------------------------------------------
public StackX(int s) // constructor
{
maxSize = s; // set array size
stackArray = new long[maxSize]; // create array
top = -1; // no items yet
}
//--------------------------------------------------------------
public void push(long j) // put item on top of stack
{
stackArray[++top] = j; // increment top, insert item
}
//--------------------------------------------------------------
public long pop() // take item from top of stack
{
return stackArray[top--]; // access item, decrement top
}
//--------------------------------------------------------------
public long peek() // peek at top of stack
{
return stackArray[top];
}
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{
return (top == -1);
}
//--------------------------------------------------------------
public boolean isFull() // true if stack is full
{
return (top == maxSize-1);
}
//--------------------------------------------------------------
} // end class StackX
////////////////////////////////////////////////////////////////
class StackApp
{
public static void main(String[] args)
{
StackX theStack = new StackX(10); // make new stack
theStack.push(20); // push items onto stack
theStack.push(40);
theStack.push(60);
theStack.push(80);
while( !theStack.isEmpty() ) // until it's empty,
{ // delete item from stack
long value = theStack.pop();
System.out.print(value); // display it
System.out.print(" ");
} // end while
System.out.println("");
} // end main()
} // end class StackApp
////////////////////////////////////////////////////////////////
3
Q
reverse a string
A
import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize;
private char[] stackArray;
private int top;
//--------------------------------------------------------------
public StackX(int max) // constructor
{
maxSize = max;
stackArray = new char[maxSize];
top = -1;
}
//--------------------------------------------------------------
public void push(char j) // put item on top of stack
{
stackArray[++top] = j;
}
//--------------------------------------------------------------
public char pop() // take item from top of stack
{
return stackArray[top--];
}
//--------------------------------------------------------------
public char peek() // peek at top of stack
{
return stackArray[top];
}
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{
return (top == -1);
}
//--------------------------------------------------------------
} // end class StackX
////////////////////////////////////////////////////////////////
class Reverser
{
private String input; // input string
private String output; // output string
//--------------------------------------------------------------
public Reverser(String in) // constructor
{ input = in; }
//--------------------------------------------------------------
public String doRev() // reverse the string
{
int stackSize = input.length(); // get max stack size
StackX theStack = new StackX(stackSize); // make stack
for(int j=0; j + output);
} // end while
} // end main()
//--------------------------------------------------------------
public static String getString() throws IOException
{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
return s;
}
//--------------------------------------------------------------
} // end class ReverseApp
////////////////////////////////////////////////////////////////
4
Q
queue
A
////////////////////////////////////////////////////////////////
class Queue
{
private int maxSize;
private long[] queArray;
private int front;
private int rear;
private int nItems;
//--------------------------------------------------------------
public Queue(int s) // constructor
{
maxSize = s;
queArray = new long[maxSize];
front = 0;
rear = -1;
nItems = 0;
}
//--------------------------------------------------------------
public void insert(long j) // put item at rear of queue
{
if(rear == maxSize-1) // deal with wraparound
rear = -1;
queArray[++rear] = j; // increment rear and insert
nItems++; // one more item
}
//--------------------------------------------------------------
public long remove() // take item from front of queue
{
long temp = queArray[front++]; // get value and incr front
if(front == maxSize) // deal with wraparound
front = 0;
nItems--; // one less item
return temp;
}
//--------------------------------------------------------------
public long peekFront() // peek at front of queue
{
return queArray[front];
}
//--------------------------------------------------------------
public boolean isEmpty() // true if queue is empty
{
return (nItems==0);
}
//--------------------------------------------------------------
public boolean isFull() // true if queue is full
{
return (nItems==maxSize);
}
//--------------------------------------------------------------
public int size() // number of items in queue
{
return nItems;
}
//--------------------------------------------------------------
} // end class Queue
////////////////////////////////////////////////////////////////
class QueueApp
{
public static void main(String[] args)
{
Queue theQueue = new Queue(5); // queue holds 5 items
theQueue.insert(10); // insert 4 items theQueue.insert(20); theQueue.insert(30); theQueue.insert(40); theQueue.remove(); // remove 3 items theQueue.remove(); // (10, 20, 30) theQueue.remove(); theQueue.insert(50); // insert 4 more items theQueue.insert(60); // (wraps around) theQueue.insert(70); theQueue.insert(80);
while( !theQueue.isEmpty() ) // remove and display
{ // all items
long n = theQueue.remove(); // (40, 50, 60, 70, 80)
System.out.print(n);
System.out.print(" ");
}
System.out.println("");
} // end main()
} // end class QueueApp
////////////////////////////////////////////////////////////////
5
Q
postfix
A
import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize;
private int[] stackArray;
private int top;
//--------------------------------------------------------------
public StackX(int size) // constructor
{
maxSize = size;
stackArray = new int[maxSize];
top = -1;
}
//--------------------------------------------------------------
public void push(int j) // put item on top of stack
{ stackArray[++top] = j; }
//--------------------------------------------------------------
public int pop() // take item from top of stack
{ return stackArray[top--]; }
//--------------------------------------------------------------
public int peek() // peek at top of stack
{ return stackArray[top]; }
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{ return (top == -1); }
//--------------------------------------------------------------
public boolean isFull() // true if stack is full
{ return (top == maxSize-1); }
//--------------------------------------------------------------
public int size() // return size
{ return top+1; }
//--------------------------------------------------------------
public int peekN(int n) // peek at index n
{ return stackArray[n]; }
//--------------------------------------------------------------
public void displayStack(String s)
{
System.out.print(s);
System.out.print("Stack (bottom-->top): ");
for(int j=0; j= '0' && ch + output);
} // end while
} // end main()
//--------------------------------------------------------------
public static String getString() throws IOException
{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
return s;
}
//--------------------------------------------------------------
} // end class PostfixApp
////////////////////////////////////////////////////////////////
6
Q
infix
A
import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize;
private char[] stackArray;
private int top;
//--------------------------------------------------------------
public StackX(int s) // constructor
{
maxSize = s;
stackArray = new char[maxSize];
top = -1;
}
//--------------------------------------------------------------
public void push(char j) // put item on top of stack
{ stackArray[++top] = j; }
//--------------------------------------------------------------
public char pop() // take item from top of stack
{ return stackArray[top--]; }
//--------------------------------------------------------------
public char peek() // peek at top of stack
{ return stackArray[top]; }
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{ return (top == -1); }
//-------------------------------------------------------------
public int size() // return size
{ return top+1; }
//--------------------------------------------------------------
public char peekN(int n) // return item at index n
{ return stackArray[n]; }
//--------------------------------------------------------------
public void displayStack(String s)
{
System.out.print(s);
System.out.print("Stack (bottom-->top): ");
for(int j=0; j< prec1) // if prec of new op less
{ // than prec of old
theStack.push(opTop); // save newly-popped op
break;
}
else // prec of new not less
output = output + opTop; // than prec of old
} // end else (it's an operator)
} // end while
theStack.push(opThis); // push new operator
} // end gotOp()
//--------------------------------------------------------------
public void gotParen(char ch)
{ // got right paren from input
while( !theStack.isEmpty() )
{
char chx = theStack.pop();
if( chx == '(' ) // if popped '('
break; // we're done
else // if popped operator
output = output + chx; // output it
} // end while
} // end popOps()
//--------------------------------------------------------------
} // end class InToPost
////////////////////////////////////////////////////////////////
class InfixApp
{
public static void main(String[] args) throws IOException
{
String input, output;
while(true)
{
System.out.print("Enter infix: ");
System.out.flush();
input = getString(); // read a string from kbd
if( input.equals("") ) // quit if [Enter]
break;
// make a translator
InToPost theTrans = new InToPost(input);
output = theTrans.doTrans(); // do the translation
System.out.println("Postfix is " + output + '\n');
} // end while
} // end main()
//--------------------------------------------------------------
public static String getString() throws IOException
{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
return s;
}
//--------------------------------------------------------------
} // end class InfixApp
////////////////////////////////////////////////////////////////
7
Q
brackets
A
import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize;
private char[] stackArray;
private int top;
//--------------------------------------------------------------
public StackX(int s) // constructor
{
maxSize = s;
stackArray = new char[maxSize];
top = -1;
}
//--------------------------------------------------------------
public void push(char j) // put item on top of stack
{
stackArray[++top] = j;
}
//--------------------------------------------------------------
public char pop() // take item from top of stack
{
return stackArray[top--];
}
//--------------------------------------------------------------
public char peek() // peek at top of stack
{
return stackArray[top];
}
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{
return (top == -1);
}
//--------------------------------------------------------------
} // end class StackX
////////////////////////////////////////////////////////////////
class BracketChecker
{
private String input; // input string
//--------------------------------------------------------------
public BracketChecker(String in) // constructor
{ input = in; }
//--------------------------------------------------------------
public void check()
{
int stackSize = input.length(); // get max stack size
StackX theStack = new StackX(stackSize); // make stack
for(int j=0; j) ) // quit if [Enter]
break;
// make a BracketChecker
BracketChecker theChecker = new BracketChecker(input);
theChecker.check(); // check brackets
} // end while
} // end main()
//--------------------------------------------------------------
public static String getString() throws IOException
{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
return s;
}
//--------------------------------------------------------------
} // end class BracketsApp
////////////////////////////////////////////////////////////////
