dsa2 min read
Rotting Oranges — Multi-Source BFS
Find minimum minutes until all oranges rot. Multi-source BFS: push all initially-rotten oranges into queue simultaneously, BFS layer by layer.
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Multi-source
7 articles
dsa1 min read
01 Matrix — Distance to Nearest 0 (Multi-Source BFS)
For each cell find distance to nearest 0. Multi-source BFS from all 0s simultaneously gives optimal O(m*n) solution.
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dsa1 min read
Walls and Gates — Multi-Source BFS from Gates
Fill each empty room with distance to nearest gate. Multi-source BFS from all gates (0) simultaneously, walls (-1) are barriers.
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dsa1 min read
Pacific Atlantic Water Flow — Two-Source DFS
Find cells that can flow to both Pacific and Atlantic oceans. Run DFS backwards from each ocean border, find intersection.
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dsa1 min read
As Far from Land as Possible — Multi-Source BFS
Find the water cell farthest from any land. Multi-source BFS from all land cells gives each water cell its min distance to land.
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dsa1 min read
Rotting Oranges — Multi-Source BFS
Find minutes until all oranges rot using multi-source BFS starting from all initially rotten oranges simultaneously.
Read →
dsa1 min read
Walls and Gates — Multi-Source BFS from All Gates
Fill each empty room with its distance to nearest gate using simultaneous multi-source BFS from all gates.
Read →