佇列&棧//最小棧
阿新 • • 發佈:2018-11-13
設計一個支援 push,pop,top 操作,並能在常數時間內檢索到最小元素的棧。
- push(x) -- 將元素 x 推入棧中。
- pop() -- 刪除棧頂的元素。
- top() -- 獲取棧頂元素。
- getMin() -- 檢索棧中的最小元素。
示例:
MinStack minStack = new MinStack(); minStack.push(-2); minStack.push(0); minStack.push(-3); minStack.getMin(); --> 返回 -3. minStack.pop(); minStack.top(); --> 返回 0. minStack.getMin(); --> 返回 -2.
class MinStack { private Stack<Integer> s1 = new Stack<>(); private Stack<Integer> s2 = new Stack<>(); /** initialize your data structure here. */ public MinStack() { } public void push(int x) { s1.push(x); if(s2.isEmpty()||s2.peek()>=x) s2.push(x); } public void pop() { int x = s1.pop(); if(s2.peek()==x) s2.pop(); } public int top() { return s1.peek(); } public int getMin() { return s2.peek(); } } /** * Your MinStack object will be instantiated and called as such: * MinStack obj = new MinStack(); * obj.push(x); * obj.pop(); * int param_3 = obj.top(); * int param_4 = obj.getMin(); */
class MinStack { private int min_val = Integer.MAX_VALUE; private Stack<Integer> s = new Stack<>(); /** initialize your data structure here. */ public MinStack() { } public void push(int x) { if(x <= min_val){ s.push(min_val); min_val = x; } s.push(x); } public void pop() { if(s.pop()==min_val) min_val = s.pop(); } public int top() { return s.peek(); } public int getMin() { return min_val; } } /** * Your MinStack object will be instantiated and called as such: * MinStack obj = new MinStack(); * obj.push(x); * obj.pop(); * int param_3 = obj.top(); * int param_4 = obj.getMin(); */
class MinStack {
private:
stack<int> s1,s2;
public:
/** initialize your data structure here. */
MinStack() {
}
void push(int x) {
s1.push(x);
if(s2.empty()||x<=s2.top())
s2.push(x);
}
void pop() {
if(s1.top()==s2.top())
s2.pop();
s1.pop();
}
int top() {
return s1.top();
}
int getMin() {
return s2.top();
}
};
/**
* Your MinStack object will be instantiated and called as such:
* MinStack obj = new MinStack();
* obj.push(x);
* obj.pop();
* int param_3 = obj.top();
* int param_4 = obj.getMin();
*/
class MinStack {
public:
/** initialize your data structure here. */
MinStack() {
min_val = INT_MAX;
}
void push(int x) {
if(x <= min_val)
{
st.push(min_val);
min_val = x;
}
st.push(x);
}
void pop() {
int t = st.top();
st.pop();
if(t == min_val){
min_val = st.top();
st.pop();
}
}
int top() {
return st.top();
}
int getMin() {
return min_val;
}
private:
int min_val;
stack<int> st;
};
/**
* Your MinStack object will be instantiated and called as such:
* MinStack obj = new MinStack();
* obj.push(x);
* obj.pop();
* int param_3 = obj.top();
* int param_4 = obj.getMin();
*/