Transition from C++ to Java (Sheet) helps you switch language faster!

Perfect 😎 I’ll make a visual translation map that you can memorize quickly while coding. I’ll organize it by common operations so you just “see C++ → Java” at a glance.

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C++ STL → Java Collections Quick Map

1. Dynamic Arrays

C++	Java	Notes
vector<int> v;	ArrayList<Integer> list = new ArrayList<>();	Dynamic size
v.push_back(x);	list.add(x);	Add element at end
v.pop_back();	list.remove(list.size()-1);	Remove last element
v[i]	list.get(i)	Access element
v.size()	list.size()	Size of array
v[i] = x;	list.set(i, x);	Modify element

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2. 2D Arrays / Lists

C++	Java	Notes
vector<vector<int>> mat;	List<List<Integer>> mat = new ArrayList<>();	Nested dynamic arrays
mat[i][j]	mat.get(i).get(j)	Access element
mat[i].push_back(x)	mat.get(i).add(x)	Append to inner list

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3. Stack

C++	Java	Notes
stack<int> st;	Stack<Integer> st = new Stack<>();	LIFO stack
st.push(x);	st.push(x);	Add element
st.pop();	st.pop();	Remove top
st.top();	st.peek();	Access top element

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4. Queue

C++	Java	Notes
queue<int> q;	Queue<Integer> q = new LinkedList<>();	FIFO queue
q.push(x);	q.offer(x);	Add element
q.pop();	q.poll();	Remove front
q.front();	q.peek();	Access front

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5. Priority Queue

C++	Java	Notes
priority_queue<int> pq;	PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder());	Max-heap
pq.push(x);	pq.add(x);	Add element
pq.top();	pq.peek();	Max element
pq.pop();	pq.poll();	Remove top

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6. Hash Map / Hash Set

C++	Java	Notes
unordered_map<int,int> mp;	HashMap<Integer,Integer> map = new HashMap<>();	Key-value store
mp[key] = val;	map.put(key,val);	Insert / update
mp.count(key)	map.containsKey(key)	Check existence
unordered_set<int> st;	HashSet<Integer> set = new HashSet<>();	Unique elements
st.insert(x)	set.add(x);	Add element
st.erase(x)	set.remove(x);	Remove element

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7. Sorting & Utility

C++	Java	Notes
sort(v.begin(), v.end());	Collections.sort(list);	Sort ascending
reverse(v.begin(), v.end());	Collections.reverse(list);	Reverse order
*min_element(v.begin(), v.end())	Collections.min(list)	Minimum
*max_element(v.begin(), v.end())	Collections.max(list)	Maximum

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8. Other Useful

C++	Java	Notes
pair<int,int> p;	Map.Entry<Integer,Integer> p; or custom Pair class	No native pair in Java
string s;	String s; or StringBuilder sb;	Strings immutable in Java
bool flag;	boolean flag;	true / false
for(int x : v)	for(int x : list)	Enhanced for-loop
v.empty()	list.isEmpty()	Check empty
const int x = 5;	final int x = 5;	Immutable variable

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💡 Tips to remember:

• Think push_back → add, pop_back → remove(last), top/front → peek.

• Vectors → ArrayLists, Sets/Maps mostly same but Java needs class wrappers.

• Most STL algorithms (sort, reverse, min/max) → Collections methods in Java.

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If you want, I can also make a compact “1-page visual map with arrows” showing C++ → Java in a diagram.
It’ll be like cheat-sheet wallpaper for your brain 😎.

Do you want me to do that next?