49 lines
1.2 KiB
JavaScript
49 lines
1.2 KiB
JavaScript
const MinStack = function () {
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this.data = []; // 内部使用数组维护栈元素
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this.minstack = [Infinity]; // 利用栈结构维护最小元素
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};
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/**
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* @param {number} val
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* @return {void}
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*/
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MinStack.prototype.push = function (val) {
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// 判断当前插入的元素是否比栈的最小元素还小
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if (val < this.minstack[this.minstack.length - 1]) this.minstack.push(val);
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this.data.push(val);
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};
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/**
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* @return {void}
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*/
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MinStack.prototype.pop = function () {
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// 判断栈顶的元素是否是最小元素，如果是，最小元素栈顶的元素也要删除
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if (this.data[this.data.length - 1] === this.minstack[this.minstack.length - 1]) {
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this.minstack.pop();
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}
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if (this.data.length) this.data.pop();
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};
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/**
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* @return {number}
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*/
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MinStack.prototype.top = function () {
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if (this.data.length) return this.data[this.data.length - 1];
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};
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/**
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* @return {number}
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*/
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MinStack.prototype.getMin = function () {
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return this.minstack[this.minstack.length - 1];
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};
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/**
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* Your MinStack object will be instantiated and called as such:
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* var obj = new MinStack()
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* obj.push(val)
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* obj.pop()
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* var param_3 = obj.top()
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* var param_4 = obj.getMin()
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*/
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