leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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commit484afbc6e24acf0ca7e8a058b666a966afb020aa
parent93006a9396d50b98bb40a900b0278244d74cb45b
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateSun, 12 Nov 2023 20:04:17 +0000

Improved Daily Problem

Diffstat:
MProblems/0815.cpp|+++++++++++++++----------

1 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/Problems/0815.cpp b/Problems/0815.cpp

@@ -1,29 +1,34 @@

class Solution {
public:
int numBusesToDestination(vector<vector<int>> &routes, int source, int target) {
int numBusesToDestination(const vector<vector<int>> &routes, int source, int target) const {
if (source == target) return 0;
unordered_map<int, vector<int>> adj;
queue<int> q;
for (int i = 0; i < routes.size(); i++) {
for (const int n : routes[i])
adj[n].push_back(i);
}
for (int i = 0; i < routes.size(); i++)
for (auto s : routes[i])
adj[s].push_back(i);
if (!adj.count(target)) return -1;
unordered_set<int> used;
queue<int> q;
q.push(source);
for (int lvl = 1; !q.empty(); lvl++) {
for (int k = q.size(); k > 0; k--) {
int crnt = q.front();
const int crnt = q.front();
q.pop();
for (int r : adj[crnt]) {
for (int v : routes[r]) {
for (const int r : adj[crnt]) {
if (used.count(-r)) continue;
used.insert(-r);
for (const int v : routes[r]) {
if (used.count(v)) continue;
if (v == target) return lvl;
used.insert(v);
q.push(v);
}
routes[r].clear();
}
adj[crnt].clear();
}
}