leetcode

Improved Daily Problem

1 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/ Problems/0802.cpp b/ Problems/0802.cpp

@@ -1,18 +1,16 @@ class Solution { public:

vector<int> eventualSafeNodes(vector<vector<int>> &graph) {

vector<int> eventualSafeNodes(const vector<vector<int>> &graph) {

int n = graph.size();

vector<int> res;

vector<bool> visited(n, false);

vector<bool> safe(n, false);

vector<bool> visited(n, false), safe(n, false);

stack<int> st; for (int i = 0; i < n; i++) { if (visited[i]) continue; st.push(i); while (!st.empty()) { int root = st.top();

st.pop();

if (root == -1) {

st.pop();

root = st.top(); st.pop(); bool s = true;

@@ -24,16 +22,52 @@ public: safe[root] = s; continue; }

if (visited[root]) continue;

if (visited[root]) {

st.pop();

continue;

};

visited[root] = true;

st.push(root);

st.push(-1); for (int c : graph[root]) if (!visited[c]) st.push(c); } }

vector<int> res;

for (int i = 0; i < n; i++) if (safe[i]) res.push_back(i); return res; } };

// Cleaner code, more memory

class Solution {

int safe[100001] = {0}, count[10001] = {0};

public:

vector<int> eventualSafeNodes(const vector<vector<int>> &graph) {

int n = graph.size();

vector<vector<int>> adj(n);

for (int i = 0; i < n; i++) {

count[i] += graph[i].size();

for (int node : graph[i]) adj[node].push_back(i);

}

queue<int> q;

for (int i = 0; i < n; i++)

if (!count[i]) q.push(i);

while (!q.empty()) {

int root = q.front();

q.pop();

safe[root] = true;

for (auto node : adj[root])

if (!--count[node]) q.push(node);

}

vector<int> res;

for (int i = 0; i < graph.size(); i++)

if (safe[i]) res.push_back(i);

return res;

}

};