def dfs(node, visited):
if node in visited: return
visited.add(node)
for child in graph[node]:
dfs(child, visited)int l = 0, r = n - 1;
while (l <= r) {
int m = l + (r - l) / 2;
if (arr[m] == x) return m;
if (arr[m] < x) l = m + 1;
else r = m - 1;
}priority_queue<pii, vector<pii>, greater<pii>> pq;
pq.push({0, start});
while(!pq.empty()){
int u = pq.top().second;
pq.pop();
}Welcome back to the Arena.
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