**Virtual Boolean Array - Google Top Interview Questions**

### Problem Statement :

Implement a boolean array which implements the following methods: BooleanArray() which initializes an array of size 2 ** 31 with all false values. void setTrue(int i) which sets the value at index i to true. void setFalse(int i) which sets the value at index i to false. void setAllTrue() which sets the value at every index to true. void setAllFalse() which sets the value at every index to false. boolean getValue(int i) which returns the value at index i. Constraints 0 ≤ n ≤ 100,000 where n is the number of method calls Example 1 Input methods = ["constructor", "getValue", "setAllTrue", "getValue", "setFalse", "getValue"] arguments = [[], [9], [], [3], [4], [4]]` Output [None, False, None, True, None, False] Explanation a = BooleanArray() a.getValue(9) == False a.setAllTrue() a.getValue(3) == True a.setFalse(4) a.getValue(4) == False Example 2 Input methods = ["constructor", "setTrue", "getValue", "setFalse", "getValue"] arguments = [[], [5], [5], [5], [5]]` Output [None, None, True, None, False] Explanation a = BooleanArray() a.setTrue(5) a.getValue(5) == True a.setFalse(5) a.getValue(5) == False

### Solution :

` ````
Solution in C++ :
class BooleanArray {
public:
bool base = false;
set<int> diffs;
BooleanArray() {
base = false;
diffs.clear();
}
void setTrue(int i) {
if (base == false)
diffs.insert(i);
else
diffs.erase(i);
}
void setFalse(int i) {
if (base == true)
diffs.insert(i);
else
diffs.erase(i);
}
void setAllTrue() {
base = true;
diffs.clear();
}
void setAllFalse() {
base = false;
diffs.clear();
}
bool getValue(int i) {
return (base == true ? (diffs.count(i) > 0 ? false : true)
: (diffs.count(i) > 0 ? true : false));
}
};
```

` ````
Solution in Java :
import java.util.*;
class BooleanArray {
public Map<Integer, Boolean> map;
public boolean allTrue;
public BooleanArray() {
map = new HashMap<>();
}
public void setTrue(int i) {
map.put(i, true);
}
public void setFalse(int i) {
map.put(i, false);
}
public void setAllTrue() {
map.clear();
allTrue = true;
}
public void setAllFalse() {
map.clear();
allTrue = false;
}
public boolean getValue(int i) {
if (map.containsKey(i))
return map.get(i);
return allTrue;
}
}
```

` ````
Solution in Python :
class BooleanArray:
def __init__(self):
self.arr = {}
self.default = False
def setTrue(self, i):
self.arr[i] = True
def setFalse(self, i):
self.arr[i] = False
def setAllTrue(self):
self.arr = {}
self.default = True
def setAllFalse(self):
self.arr = {}
self.default = False
def getValue(self, i):
if i not in self.arr:
return self.default
return self.arr[i]
immortal
96
1 year ago
Even more compact memory footprint depending upon assignment.
class BooleanArray:
def __init__(self):
self.state = False
self.d = set()
def clear(self):
self.d = set()
def setTrue(self, i):
if not self.state:
self.d.add(i)
elif i in self.d:
self.d.remove(i)
def setFalse(self, i):
if self.state:
self.d.add(i)
elif i in self.d:
self.d.remove(i)
def setAllTrue(self):
self.clear()
self.state = True
def setAllFalse(self):
self.clear()
self.state = False
def getValue(self, i):
if i in self.d:
return not self.state
return self.state
```

## View More Similar Problems

## Castle on the Grid

You are given a square grid with some cells open (.) and some blocked (X). Your playing piece can move along any row or column until it reaches the edge of the grid or a blocked cell. Given a grid, a start and a goal, determine the minmum number of moves to get to the goal. Function Description Complete the minimumMoves function in the editor. minimumMoves has the following parameter(s):

View Solution →## Down to Zero II

You are given Q queries. Each query consists of a single number N. You can perform any of the 2 operations N on in each move: 1: If we take 2 integers a and b where , N = a * b , then we can change N = max( a, b ) 2: Decrease the value of N by 1. Determine the minimum number of moves required to reduce the value of N to 0. Input Format The first line contains the integer Q.

View Solution →## Truck Tour

Suppose there is a circle. There are N petrol pumps on that circle. Petrol pumps are numbered 0 to (N-1) (both inclusive). You have two pieces of information corresponding to each of the petrol pump: (1) the amount of petrol that particular petrol pump will give, and (2) the distance from that petrol pump to the next petrol pump. Initially, you have a tank of infinite capacity carrying no petr

View Solution →## Queries with Fixed Length

Consider an -integer sequence, . We perform a query on by using an integer, , to calculate the result of the following expression: In other words, if we let , then you need to calculate . Given and queries, return a list of answers to each query. Example The first query uses all of the subarrays of length : . The maxima of the subarrays are . The minimum of these is . The secon

View Solution →## QHEAP1

This question is designed to help you get a better understanding of basic heap operations. You will be given queries of types: " 1 v " - Add an element to the heap. " 2 v " - Delete the element from the heap. "3" - Print the minimum of all the elements in the heap. NOTE: It is guaranteed that the element to be deleted will be there in the heap. Also, at any instant, only distinct element

View Solution →## Jesse and Cookies

Jesse loves cookies. He wants the sweetness of all his cookies to be greater than value K. To do this, Jesse repeatedly mixes two cookies with the least sweetness. He creates a special combined cookie with: sweetness Least sweet cookie 2nd least sweet cookie). He repeats this procedure until all the cookies in his collection have a sweetness > = K. You are given Jesse's cookies. Print t

View Solution →