feat: python impl for 0-1 BFS #1380
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adamant-pwn
reviewed
Oct 24, 2024
Comment on lines
+20
to
40
| === "C++" | ||
| ```cpp | ||
| d.assign(n, INF); | ||
| d[s] = 0; | ||
| set<pair<int, int>> q; | ||
| q.insert({0, s}); | ||
| while (!q.empty()) { | ||
| int v = q.begin()->second; | ||
| q.erase(q.begin()); | ||
|
|
||
| for (auto edge : adj[v]) { | ||
| int u = edge.first; | ||
| int w = edge.second; | ||
|
|
||
| if (d[v] + w < d[u]) { | ||
| q.erase({d[u], u}); | ||
| d[u] = d[v] + w; | ||
| q.insert({d[u], u}); | ||
| } | ||
| } | ||
| } |
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Suggested change
| === "C++" | |
| ```cpp | |
| d.assign(n, INF); | |
| d[s] = 0; | |
| set<pair<int, int>> q; | |
| q.insert({0, s}); | |
| while (!q.empty()) { | |
| int v = q.begin()->second; | |
| q.erase(q.begin()); | |
| for (auto edge : adj[v]) { | |
| int u = edge.first; | |
| int w = edge.second; | |
| if (d[v] + w < d[u]) { | |
| q.erase({d[u], u}); | |
| d[u] = d[v] + w; | |
| q.insert({d[u], u}); | |
| } | |
| } | |
| } | |
| === "C++" | |
| ```cpp | |
| d.assign(n, INF); | |
| d[s] = 0; | |
| priority_queue<pair<int, int>> q = {{0, s}}; | |
| while (!empty(q)) { | |
| int [dv, v] = q.top(); | |
| q.pop(); | |
| if (-dv == d[v]) { | |
| for (auto [u, w] : adj[v]) { | |
| if (d[v] + w < d[u]) { | |
| d[u] = d[v] + w; | |
| q.insert({-d[u], u}); | |
| } | |
| } | |
| } | |
| } |
Probably best to make this consistent with Python then. Also remove the comment about "set" above if this is incorporated.
adamant-pwn
reviewed
Oct 24, 2024
Comment on lines
+75
to
93
| vector<int> d(n, INF); | ||
| d[s] = 0; | ||
| deque<int> q; | ||
| q.push_front(s); | ||
| while (!q.empty()) { | ||
| int v = q.front(); | ||
| q.pop_front(); | ||
| for (auto edge : adj[v]) { | ||
| int u = edge.first; | ||
| int w = edge.second; | ||
| if (d[v] + w < d[u]) { | ||
| d[u] = d[v] + w; | ||
| if (w == 1) | ||
| q.push_back(u); | ||
| else | ||
| q.push_front(u); | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
Suggested change
| vector<int> d(n, INF); | |
| d[s] = 0; | |
| deque<int> q; | |
| q.push_front(s); | |
| while (!q.empty()) { | |
| int v = q.front(); | |
| q.pop_front(); | |
| for (auto edge : adj[v]) { | |
| int u = edge.first; | |
| int w = edge.second; | |
| if (d[v] + w < d[u]) { | |
| d[u] = d[v] + w; | |
| if (w == 1) | |
| q.push_back(u); | |
| else | |
| q.push_front(u); | |
| } | |
| } | |
| } | |
| vector<int> d(n, INF); | |
| d[s] = 0; | |
| deque<int> q = {s}; | |
| while (!empty(q)) { | |
| int v = q.front(); | |
| q.pop_front(); | |
| for (auto [u, w] : adj[v]) { | |
| if (d[v] + w < d[u]) { | |
| d[u] = d[v] + w; | |
| if (w == 1) | |
| q.push_back(u); | |
| else | |
| q.push_front(u); | |
| } | |
| } | |
| } |
|
I think it's best to also rewrite C++ code with a newer standard to match the Python style. But could you please test both implementations on one of the example problems in the article? |
|
Updates? |
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Adding python implementation, fixing a minor grammatical error.
Recreating #1336 against the new base (
main).