Algorithm Notes
Summary: Unique Paths — notes not yet curated.
Time: Estimate via loops/recurrences; common classes: O(1), O(log n), O(n), O(n log n), O(n^2)
Space: Count auxiliary structures and recursion depth.
Tip: See the Big-O Guide for how to derive bounds and compare trade-offs.
Big-O Guide
Source
"""
Unique Paths
TODO: Add problem description
"""
from src.interview_workbook.leetcode._registry import register_problem
from src.interview_workbook.leetcode._types import Category, Difficulty
class Solution:
def solve(self, *args) -> int:
"""Return number of unique paths in m x n grid (only right/down moves)."""
if len(args) != 2:
return ""
m, n = args
dp = [[1] * n for _ in range(m)]
for i in range(1, m):
for j in range(1, n):
dp[i][j] = dp[i - 1][j] + dp[i][j - 1]
return dp[m - 1][n - 1]
def demo():
"""Run a demo for the Unique Paths problem."""
solver = Solution()
m, n = 3, 7
result = solver.solve(m, n)
return str(result)
register_problem(
id=62,
slug="unique_paths",
title="Unique Paths",
category=Category.DP_2D,
difficulty=Difficulty.MEDIUM,
tags=["math", "dynamic_programming", "combinatorics"],
url="https://leetcode.com/problems/unique-paths/",
notes="",
)