Graph ·

LeetCode 851: Loud and Rich

2026-04-13·2 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Loud and Rich, rebuilt from the original learning note

LeetCode 802: Find Eventual Safe States

2026-04-13·3 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Find Eventual Safe States, rebuilt from the original learning note

LeetCode 1203: Sort Items by Groups Respecting Dependencies

2026-04-13·3 mins

LeetCode Hard Graph Topological-Sort

LeetCode note for Sort Items by Groups Respecting Dependencies, rebuilt from the original learning note

LeetCode 3898: Find the Degree of Each Vertex

2026-04-12·1 min

LeetCode Easy Graph Matrix Array

LeetCode 3898 note: the number of ones in row i of the adjacency matrix is vertex i’s degree

LeetCode 310: Minimum Height Trees

2026-04-11·3 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Minimum Height Trees, rebuilt from the original learning note

LeetCode 2115: Find All Possible Recipes from Given Supplies

2026-04-11·3 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Find All Possible Recipes from Given Supplies, rebuilt from the original learning note

LeetCode 2192: All Ancestors of a Node in a DAG

2026-04-08·3 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for All Ancestors of a Node in a DAG, rebuilt from the original learning note

LeetCode 210: Course Schedule II

2026-04-08·2 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Course Schedule II, rebuilt from the original learning note

LeetCode 207: Course Schedule

2026-04-08·2 mins

LeetCode Medium Graph Topological-Sort

LeetCode note for Course Schedule, rebuilt from the original learning note

LeetCode 1971: Find if Path Exists in Graph

2026-04-08·2 mins

LeetCode Easy Graph Union-Find

LeetCode note for Find if Path Exists in Graph, rebuilt from the original learning note

LeetCode 3820: Pythagorean Distance Nodes in a Tree

2026-01-25·2 mins

LeetCode Medium Tree Bfs Graph

LeetCode 3820 note: three BFS runs give every node’s distance to the three targets

LeetCode 1782: Count Pairs Of Nodes

2026-01-24·3 mins

LeetCode Hard Two-Pointers Graph Sorting Hash-Table Counting

LeetCode 1782 note: count pairs with deg[a] + deg[b] > q using sorted degrees and converging pointers, then correct the over-count for pairs that share edges