7.13 — Quick Revision: Queue

<< Overview

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Key concepts

Operation	Array Queue	Linked Queue	Circular
Enqueue	O(1)	O(1)	O(1)
Dequeue	O(n) shift	O(1)	O(1)
Peek	O(1)	O(1)	O(1)
Space	Dynamic	O(n)	Fixed

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Self-check drill

SC-001

• Q: Queue order?
• A: FIFO — First In, First Out

SC-002

• Q: Enqueue time?
• A: O(1)

SC-003

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-004

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-005

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-006

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-007

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-008

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-009

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-010

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-011

• Q: Queue order?
• A: FIFO — First In, First Out

SC-012

• Q: Enqueue time?
• A: O(1)

SC-013

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-014

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-015

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-016

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-017

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-018

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-019

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-020

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-021

• Q: Queue order?
• A: FIFO — First In, First Out

SC-022

• Q: Enqueue time?
• A: O(1)

SC-023

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-024

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-025

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-026

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-027

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-028

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-029

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-030

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-031

• Q: Queue order?
• A: FIFO — First In, First Out

SC-032

• Q: Enqueue time?
• A: O(1)

SC-033

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-034

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-035

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-036

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-037

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-038

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-039

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-040

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-041

• Q: Queue order?
• A: FIFO — First In, First Out

SC-042

• Q: Enqueue time?
• A: O(1)

SC-043

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-044

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-045

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-046

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-047

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-048

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-049

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-050

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-051

• Q: Queue order?
• A: FIFO — First In, First Out

SC-052

• Q: Enqueue time?
• A: O(1)

SC-053

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-054

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-055

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-056

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-057

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-058

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-059

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-060

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-061

• Q: Queue order?
• A: FIFO — First In, First Out

SC-062

• Q: Enqueue time?
• A: O(1)

SC-063

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-064

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-065

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-066

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-067

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-068

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-069

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-070

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-071

• Q: Queue order?
• A: FIFO — First In, First Out

SC-072

• Q: Enqueue time?
• A: O(1)

SC-073

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-074

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-075

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-076

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-077

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-078

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-079

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-080

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-081

• Q: Queue order?
• A: FIFO — First In, First Out

SC-082

• Q: Enqueue time?
• A: O(1)

SC-083

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-084

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-085

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-086

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-087

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-088

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-089

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-090

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-091

• Q: Queue order?
• A: FIFO — First In, First Out

SC-092

• Q: Enqueue time?
• A: O(1)

SC-093

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-094

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-095

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-096

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-097

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-098

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-099

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-100

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-101

• Q: Queue order?
• A: FIFO — First In, First Out

SC-102

• Q: Enqueue time?
• A: O(1)

SC-103

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-104

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-105

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-106

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-107

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-108

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-109

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-110

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-111

• Q: Queue order?
• A: FIFO — First In, First Out

SC-112

• Q: Enqueue time?
• A: O(1)

SC-113

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-114

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-115

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-116

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-117

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-118

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-119

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-120

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-121

• Q: Queue order?
• A: FIFO — First In, First Out

SC-122

• Q: Enqueue time?
• A: O(1)

SC-123

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-124

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-125

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-126

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-127

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-128

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-129

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-130

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-131

• Q: Queue order?
• A: FIFO — First In, First Out

SC-132

• Q: Enqueue time?
• A: O(1)

SC-133

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-134

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-135

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-136

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-137

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-138

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-139

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-140

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-141

• Q: Queue order?
• A: FIFO — First In, First Out

SC-142

• Q: Enqueue time?
• A: O(1)

SC-143

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-144

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-145

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-146

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-147

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-148

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-149

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-150

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-151

• Q: Queue order?
• A: FIFO — First In, First Out

SC-152

• Q: Enqueue time?
• A: O(1)

SC-153

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-154

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-155

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-156

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-157

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-158

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-159

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-160

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-161

• Q: Queue order?
• A: FIFO — First In, First Out

SC-162

• Q: Enqueue time?
• A: O(1)

SC-163

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-164

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-165

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-166

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-167

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-168

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-169

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-170

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-171

• Q: Queue order?
• A: FIFO — First In, First Out

SC-172

• Q: Enqueue time?
• A: O(1)

SC-173

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-174

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-175

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-176

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-177

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-178

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-179

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-180

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-181

• Q: Queue order?
• A: FIFO — First In, First Out

SC-182

• Q: Enqueue time?
• A: O(1)

SC-183

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-184

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-185

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-186

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-187

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-188

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-189

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-190

• Q: Sliding window max?
• A: Deque maintaining decreasing order

SC-191

• Q: Queue order?
• A: FIFO — First In, First Out

SC-192

• Q: Enqueue time?
• A: O(1)

SC-193

• Q: Dequeue (array)?
• A: O(n) shift, O(1) linked list

SC-194

• Q: Circular queue?
• A: Modulo for wrapping front/rear

SC-195

• Q: Queue vs Stack?
• A: Queue: FIFO, Stack: LIFO

SC-196

• Q: BFS uses?
• A: Queue for level-by-level traversal

SC-197

• Q: Priority queue?
• A: Dequeue by priority, not order

SC-198

• Q: Deque?
• A: Double-ended queue, add/remove both ends

SC-199

• Q: Queue with 2 stacks?
• A: Push to stack1, pop from stack2

SC-200

• Q: Sliding window max?
• A: Deque maintaining decreasing order