Doordash Placement Papers 2026

Section 2: Logical Reasoning

Section 3: Technical MCQs

Section 4: Coding Problems

Question 16

Problem: Implement a delivery route optimization algorithm that finds the shortest path to deliver multiple orders.

Solution:

import heapq
from typing import List, Tuple, Dict

class DeliveryRouteOptimizer:
    def __init__(self):
        self.graph = {}  # location -> list of (neighbor, distance)
    
    def add_location(self, location: str):
        """Add a delivery location"""
        if location not in self.graph:
            self.graph[location] = []
    
    def add_road(self, location1: str, location2: str, distance: float):
        """Add a road between two locations"""
        if location1 not in self.graph:
            self.add_location(location1)
        if location2 not in self.graph:
            self.add_location(location2)
        
        self.graph[location1].append((location2, distance))
        self.graph[location2].append((location1, distance))
    
    def shortest_path(self, start: str, end: str) -> Tuple[List[str], float]:
        """Find shortest path using Dijkstra's algorithm"""
        if start not in self.graph or end not in self.graph:
            return [], float('inf')
        
        # Priority queue: (distance, current_location, path)
        pq = [(0, start, [start])]
        visited = set()
        
        while pq:
            current_dist, current_loc, path = heapq.heappop(pq)
            
            if current_loc in visited:
                continue
            
            visited.add(current_loc)
            
            # Check if we reached destination
            if current_loc == end:
                return path, current_dist
            
            # Explore neighbors
            for neighbor, edge_dist in self.graph[current_loc]:
                if neighbor not in visited:
                    new_dist = current_dist + edge_dist
                    new_path = path + [neighbor]
                    heapq.heappush(pq, (new_dist, neighbor, new_path))
        
        return [], float('inf')
    
    def optimize_delivery_route(self, start: str, deliveries: List[str]) -> List[str]:
        """
        Optimize delivery route for multiple deliveries (Traveling Salesman Problem approximation)
        Uses nearest neighbor heuristic
        """
        if not deliveries:
            return [start]
        
        current = start
        unvisited = set(deliveries)
        route = [start]
        total_distance = 0
        
        while unvisited:
            # Find nearest unvisited delivery
            nearest = None
            min_dist = float('inf')
            
            for delivery in unvisited:
                path, dist = self.shortest_path(current, delivery)
                if dist < min_dist:
                    min_dist = dist
                    nearest = delivery
            
            if nearest is None:
                break
            
            # Add to route
            route.append(nearest)
            total_distance += min_dist
            current = nearest
            unvisited.remove(nearest)
        
        # Return to start
        path_back, dist_back = self.shortest_path(current, start)
        total_distance += dist_back
        
        return route, total_distance
    
    def multiple_dasher_routing(self, dashers: List[str], deliveries: List[str]) -> Dict[str, List[str]]:
        """
        Assign deliveries to multiple dashers optimally
        Simple greedy assignment
        """
        # Sort deliveries by distance from each dasher's starting point
        assignments = {dasher: [] for dasher in dashers}
        
        for delivery in deliveries:
            # Find dasher closest to this delivery
            best_dasher = None
            best_distance = float('inf')
            
            for dasher in dashers:
                path, distance = self.shortest_path(dasher, delivery)
                if distance < best_distance:
                    best_distance = distance
                    best_dasher = dasher
            
            if best_dasher:
                assignments[best_dasher].append(delivery)
        
        return assignments

# Test
optimizer = DeliveryRouteOptimizer()

# Add locations and roads
locations = ["Restaurant", "Customer1", "Customer2", "Customer3", "Customer4"]
for loc in locations:
    optimizer.add_location(loc)

# Add roads with distances
optimizer.add_road("Restaurant", "Customer1", 2.5)
optimizer.add_road("Restaurant", "Customer2", 3.0)
optimizer.add_road("Customer1", "Customer2", 1.5)
optimizer.add_road("Customer2", "Customer3", 2.0)
optimizer.add_road("Customer3", "Customer4", 1.0)
optimizer.add_road("Customer1", "Customer4", 2.5)

# Test shortest path
path, distance = optimizer.shortest_path("Restaurant", "Customer4")
print(f"Shortest path: {path}, Distance: {distance}")

# Test delivery route optimization
deliveries = ["Customer1", "Customer2", "Customer3", "Customer4"]
route, total_dist = optimizer.optimize_delivery_route("Restaurant", deliveries)
print(f"Optimized route: {route}, Total distance: {total_dist}")

# Test multiple dasher routing
dashers = ["Dasher1", "Dasher2"]
assignments = optimizer.multiple_dasher_routing(dashers, deliveries)
print(f"Dasher assignments: {assignments}")

Time Complexity: O(V²) for nearest neighbor TSP approximation
Space Complexity: O(V + E) for graph storage

Question 17

Problem: Design a real-time order tracking system for DoorDash.

Solution:

from datetime import datetime
from enum import Enum
from typing import Dict, List, Optional
import asyncio

class OrderStatus(Enum):
    PLACED = "placed"
    CONFIRMED = "confirmed"
    PREPARING = "preparing"
    READY = "ready"
    PICKED_UP = "picked_up"
    ON_THE_WAY = "on_the_way"
    DELIVERED = "delivered"
    CANCELLED = "cancelled"

class OrderEvent:
    def __init__(self, order_id: str, status: OrderStatus, timestamp=None, location=None, dasher_id=None):
        self.order_id = order_id
        self.status = status
        self.timestamp = timestamp or datetime.now()
        self.location = location  # Optional: GPS coordinates
        self.dasher_id = dasher_id  # Optional: Dasher assigned
    
    def to_dict(self):
        return {
            "order_id": self.order_id,
            "status": self.status.value,
            "timestamp": self.timestamp.isoformat(),
            "location": self.location,
            "dasher_id": self.dasher_id
        }

class OrderTracker:
    def __init__(self):
        self.orders = {}  # order_id -> list of OrderEvent
        self.subscribers = {}  # order_id -> list of callback functions
        self.status_handlers = {}  # status -> handler function
    
    def place_order(self, order_id: str, customer_id: str, restaurant_id: str, items: List[str]):
        """Place a new order"""
        if order_id in self.orders:
            raise ValueError(f"Order {order_id} already exists")
        
        initial_event = OrderEvent(order_id, OrderStatus.PLACED)
        self.orders[order_id] = {
            "customer_id": customer_id,
            "restaurant_id": restaurant_id,
            "items": items,
            "events": [initial_event],
            "current_status": OrderStatus.PLACED,
            "created_at": datetime.now()
        }
        
        self._notify_subscribers(order_id, initial_event)
        return order_id
    
    def update_status(self, order_id: str, status: OrderStatus, **kwargs):
        """Update order status"""
        if order_id not in self.orders:
            raise ValueError(f"Order {order_id} not found")
        
        order = self.orders[order_id]
        
        # Validate status transition
        if not self._is_valid_transition(order["current_status"], status):
            raise ValueError(f"Invalid status transition: {order['current_status']} -> {status}")
        
        # Create event
        event = OrderEvent(order_id, status, **kwargs)
        order["events"].append(event)
        order["current_status"] = status
        
        # Call status handler if exists
        if status in self.status_handlers:
            self.status_handlers[status](order_id, order)
        
        # Notify subscribers

## Frequently Asked Questions

### What is the expected salary range for DoorDash placements in 2026?

DoorDash compensation typically includes a base salary plus performance-based incentives, and in many roles there may also be stock/RSUs depending on location and level. For 2026 hiring, candidates often see competitive offers relative to other tech companies, with the final package varying based on role (SDE, SRE, Data, etc.), experience, and interview performance.

### What are the eligibility criteria for DoorDash placements 2026?

Eligibility usually requires you to be in your pre-final/final year (or have the required years of experience) and meet the minimum academic and degree requirements set by the hiring team. You should also be prepared to demonstrate strong fundamentals in data structures and algorithms, along with relevant skills for the specific role you apply for.

### How difficult are DoorDash placement rounds for 2026?

The difficulty is generally considered moderate to high because DoorDash interviews often test problem-solving depth, coding efficiency, and clear communication. Many candidates find the coding and system design/behavioral components challenging if they haven’t practiced under timed conditions and reviewed common patterns.

### What preparation tips work best for DoorDash placement papers 2026?

Focus on mastering core DSA topics (arrays, strings, hashing, stacks/queues, trees, graphs, DP) and practice coding problems with clean, optimized solutions. Also prepare for behavioral questions using STAR format, and do mock interviews to improve speed, correctness, and explanation quality.

### What are the typical interview rounds in DoorDash placements 2026?

A common flow includes an online assessment (coding), followed by one or more technical interviews (coding and/or system design), and then behavioral/HR rounds. Some candidates may also face additional rounds depending on the role and hiring cycle, but the core theme remains: problem-solving plus communication.

### What common topics appear in DoorDash placement papers 2026?

You can expect frequent questions on arrays/strings, hashing, two pointers, sliding window, linked lists, trees (BST/DFS/BFS), graphs, and dynamic programming. For system design or advanced rounds, topics like scalability, caching, API design, and reliability are often discussed at a conceptual level.

### How do I apply for DoorDash placements 2026?

You typically apply through DoorDash’s official careers page or via campus/college placement portals if your institute has a tie-up. After applying, keep an eye on email notifications for online assessments and ensure your resume highlights relevant projects, internships, and measurable outcomes.

### What is the selection rate for DoorDash placements 2026?

A precise selection rate isn’t publicly fixed and can vary widely by campus, role, and number of applicants in a given cycle. Generally, the conversion depends heavily on performance in the coding assessment and technical interviews, so consistent practice and strong fundamentals significantly improve your chances.


**Honesty about data:** this guide leans on public candidate reports and official sources, so no number here is guaranteed for your specific drive. Confirm on the official portal, and treat candidate-reported cut-offs as a planning range, not a promise.