From 0377164732f54b7d6144ea3eb05092f6cce00146 Mon Sep 17 00:00:00 2001 From: Zachary Zhu Date: Sat, 15 Jun 2019 16:53:15 -0700 Subject: [PATCH 1/2] Corrected wrong DFS implementation --- graphs/DFS.py | 1 - 1 file changed, 1 deletion(-) diff --git a/graphs/DFS.py b/graphs/DFS.py index c9843ca25382..68bf60e3c298 100644 --- a/graphs/DFS.py +++ b/graphs/DFS.py @@ -16,7 +16,6 @@ def dfs(graph, start): to the node's children onto the iterator stack. When the iterator at the top of the stack terminates, we'll pop it off the stack.""" explored, stack = set(), [start] - explored.add(start) while stack: v = stack.pop() # one difference from BFS is to pop last element here instead of first one From c896550cbd77d68676598c989a4e9ed164a5830c Mon Sep 17 00:00:00 2001 From: Zachary Zhu Date: Wed, 19 Jun 2019 00:42:38 -0700 Subject: [PATCH 2/2] changed list into hash set for dijkstra priority queue implementation. --- graphs/dijkstra.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/graphs/dijkstra.py b/graphs/dijkstra.py index 6b08b28fcfd3..4b6bc347b061 100644 --- a/graphs/dijkstra.py +++ b/graphs/dijkstra.py @@ -20,12 +20,12 @@ def dijkstra(graph, start, end): heap = [(0, start)] # cost from start node,end node - visited = [] + visited = set() while heap: (cost, u) = heapq.heappop(heap) if u in visited: continue - visited.append(u) + visited.add(u) if u == end: return cost for v, c in G[u]: