1. /**
    2.  * @param {number} maxSize
    3.  */
    6. var CustomStack = function(maxSize) {
    7.   this.stack = [];
    8.   this.maxSize = maxSize;
    9. };
    11. /** 
    12.  * @param {number} x
    13.  * @return {void}
    14.  */
    15. CustomStack.prototype.push = function(x) {
    16.   if (this.stack.length < this.maxSize) {
    17.     this.stack[this.stack.length] = x;
    18.   }
    19. };
    21. /**
    22.  * @return {number}
    23.  */
    24. CustomStack.prototype.pop = function() {
    25.   if (this.stack.length) {
    26.     const top = this.stack[this.stack.length-1];
    27.     this.stack.length--
    28.     return top;
    29.   }
    30.   this.stack.length = 0;
    31.   this.top = 0;
    32.   return -1
    33. };
    35. /** 
    36.  * @param {number} k 
    37.  * @param {number} val
    38.  * @return {void}
    39.  */
    40. CustomStack.prototype.increment = function(k, val) {
    41.   k = Math.min(this.stack.length, k);
    42.   for (let i = 0; i < k; i++) {
    43.     this.stack[i] += val
    44.   }
    45. };
    46. var customStack = new CustomStack(3)
    47. customStack.push(1);
    48. customStack.push(2);
    49. customStack.pop();
    50. customStack.push(2);
    51. customStack.push(3);
    52. customStack.push(4);
    53. customStack.increment(5, 100);                // 栈变为 [101, 102, 103]
    54. //customStack.increment(2, 100);                // 栈变为 [201, 202, 103]
    55. // customStack.pop();                          // 返回 103 --> 返回栈顶值 103，栈变为 [201, 202]
    56. // customStack.pop();                            // 返回 202 --> 返回栈顶值 202，栈变为 [201]
    57. // customStack.pop();                            // 返回 201 --> 返回栈顶值 201，栈变为 []
    58. // customStack.pop();   
    59. console.log(customStack);
    61. /**
    62.  * Your CustomStack object will be instantiated and called as such:
    63.  * var obj = new CustomStack(maxSize)
    64.  * obj.push(x)
    65.  * var param_2 = obj.pop()
    66.  * obj.increment(k,val)
    67.  */