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87 lines
1.6 KiB
Markdown
87 lines
1.6 KiB
Markdown
# [155. Min Stack](https://leetcode.com/problems/min-stack/)
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## 题目
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Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
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push(x) -- Push element x onto stack.
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pop() -- Removes the element on top of the stack.
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top() -- Get the top element.
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getMin() -- Retrieve the minimum element in the stack.
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**Example**:
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```
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MinStack minStack = new MinStack();
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minStack.push(-2);
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minStack.push(0);
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minStack.push(-3);
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minStack.getMin(); --> Returns -3.
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minStack.pop();
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minStack.top(); --> Returns 0.
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minStack.getMin(); --> Returns -2.
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```
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## 题目大意
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这道题是一个数据结构实现题。要求实现一个栈的类，实现 push()、pop()、top()、getMin()。
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## 解题思路
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按照题目要求实现即可。
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## 代码
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```go
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package leetcode
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// MinStack define
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type MinStack struct {
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elements, min []int
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l int
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}
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/** initialize your data structure here. */
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// Constructor155 define
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func Constructor155() MinStack {
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return MinStack{make([]int, 0), make([]int, 0), 0}
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}
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// Push define
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func (this *MinStack) Push(x int) {
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this.elements = append(this.elements, x)
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if this.l == 0 {
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this.min = append(this.min, x)
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} else {
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min := this.GetMin()
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if x < min {
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this.min = append(this.min, x)
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} else {
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this.min = append(this.min, min)
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}
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}
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this.l++
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}
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func (this *MinStack) Pop() {
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this.l--
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this.min = this.min[:this.l]
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this.elements = this.elements[:this.l]
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}
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func (this *MinStack) Top() int {
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return this.elements[this.l-1]
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}
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func (this *MinStack) GetMin() int {
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return this.min[this.l-1]
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}
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``` |