标签：ret sem min turn returns 网上 removes top data
Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Removes the element on top of the stack. top() -- Get the top element. getMin() -- Retrieve the minimum element in the stack. Example: MinStack minStack = new MinStack(); minStack.push(-2); minStack.push(0); minStack.push(-3); minStack.getMin(); --> Returns -3. minStack.pop(); minStack.top(); --> Returns 0. minStack.getMin(); --> Returns -2.
public class MinStack {
int min = 0;
private Stack<Integer> s = new Stack<>();
/** initialize your data structure here. */
public MinStack() {
s = new Stack<>();
}
public void push(int x) {
if (s.isEmpty()) {
s.push(x);
s.push(x);
min = x;
}else if (x <= min) {
min = x;
s.push(min);
s.push(x);
} else {
s.push(min);
s.push(x);
}
}
public void pop() {
if (min == (s.pop())) {
s.pop();
if (!s.isEmpty()) {
int temp = s.pop();
min = s.pop();
s.push(min);
s.push(temp);
}
} else {
min = s.pop();
}
}
public int top() {
return s.peek();
}
public int getMin() {
if (!s.isEmpty()) {
return min;
}
return 0;
}
}
这个简洁点, 网上的, 自己的那个就不错
public class MinStack {
Stack<Integer> stack;
int min=Integer.MAX_VALUE;;
/** initialize your data structure here. */
public MinStack() {
stack = new Stack<>();
}
public void push(int x) {
if(x<=min)
{
stack.push(min);
min = x;
}
stack.push(x);
}
public void pop() {
if(stack.pop() == min)
min = stack.pop();
}
public int top() {
return stack.peek();
}
public int getMin() {
return min;
}
}
标签：ret sem min turn returns 网上 removes top data
原文地址：http://www.cnblogs.com/apanda009/p/7295429.html
