Create 面试题59 - II. 队列的最大值.js

Author: yinxin630

面试题59 - II. 队列的最大值.js

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+var MaxQueue = function() {
+    this.queue = [];
+    this.max = [];
+};
+
+/**
+ * @return {number}
+ */
+MaxQueue.prototype.max_value = function() {
+    if (this.max.length) {
+        return this.max[0];
+    } else {
+        return -1;
+    }
+};
+
+/** 
+ * @param {number} value
+ * @return {void}
+ */
+MaxQueue.prototype.push_back = function(value) {
+    this.queue.push(value);
+    while (this.max.length  >= 0 && this.max[this.max.length - 1] < value) {
+        this.max.pop();
+    }
+    this.max.push(value);
+};
+
+/**
+ * @return {number}
+ */
+MaxQueue.prototype.pop_front = function() {
+    if (this.queue.length === 0) {
+        return -1;
+    }
+    const value = this.queue.shift();
+    if (value === this.max[0]) {
+        this.max.shift();
+    }
+    return value;
+};
+
+/**
+ * Your MaxQueue object will be instantiated and called as such:
+ * var obj = new MaxQueue()
+ * var param_1 = obj.max_value()
+ * obj.push_back(value)
+ * var param_3 = obj.pop_front()
+ */