CppDSA/51_deQueue.cpp at main · Rishav07-05/CppDSA · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
#include <bits/stdc++.h>
using namespace std;

class Queue{
    int *arr;
    int front;
    int rear;
    int size;

public:
    Queue(){
        size = 100000;
        arr = new int[size];
        front = rear = -1;
    }

    bool pushFront(int x)
    {
        if((front == 0 && rear == size - 1) || (rear == (front - 1) % (size - 1))){
            return false;
        }
        else if(front == -1){
            front = rear = 0;
        }
        else if(front == 0 && rear != size - 1){
            front = size - 1;
        }
        else{
            front--;
        }
        arr[front] = x;
        return true;
    }

    bool pushRear(int x)
    {
        if(isFull()){
            return false;
        }
        else if(isEmpty()){
            front = rear = 0;
        }
        else if(rear == size - 1 && front != 0){
            rear = 0;
        }
        else{
            rear++;
        }
        arr[rear] = x;
        return true;
    }

    int popFront(){
        if(front == -1){
            return -1;
        }
        int ans = arr[front];
        arr[front] = -1;
        if(front == rear){
            front = rear = -1;
        }
        else if(front == size - 1){
            front = 0;
        }
        else{
            front++;
        }
        return ans;
    }

    int popRear(){
        if(front == -1){
            return -1;
        }
        int ans = arr[rear];
        arr[rear] = -1;
        if(front == rear){
            front = rear = -1;
        }
        else if(rear == 0){
            rear = size - 1;
        }
        else{
            rear--;
        }
        return ans;
    }

    int getFront(){
        if(isEmpty()){
            return -1;
        }
        return arr[front];
    }

    int getRear(){
        if(isEmpty()){
            return -1;
        }
        return arr[rear];
    }

    bool isEmpty()
    {
        if(front == -1)
            return true;
        else
            return false;
    }

    bool isFull()
    {
        if ((front == 0 && rear == size - 1) || ( front != 0 && rear ==(front - 1) % (size - 1))){
            return true;
        }
        else{
            return false;
        }
    }
};

int main(){
    // deque<int> d;

    // d.push_front(13);
    // d.push_front(12);
    // d.push_back(11);
    // d.push_back(14);
    // d.pop_back();

    // cout << d.front() << endl;
    // cout << d.back() << endl;

    Queue q;

    q.pushFront(19);
    q.pushFront(29);
    q.pushFront(21);
    q.pushRear(11);
    q.pushRear(14);
    q.pushRear(24);
    q.popRear();

    cout << "Front element: " << q.getFront() << endl;
    cout << "Rear element: " << q.getRear() << endl;
}