1381. 设计一个支持增量操作的栈
请你设计一个支持下述操作的栈。
实现自定义栈类 CustomStack ：
CustomStack(int maxSize)：用 maxSize 初始化对象，maxSize 是栈中最多能容纳的元素数量，栈在增长到 maxSize 之后则不支持 push 操作。void push(int x)：如果栈还未增长到 maxSize ，就将 x 添加到栈顶。int pop()：弹出栈顶元素，并返回栈顶的值，或栈为空时返回 -1 。void inc(int k, int val)：栈底的 k 个元素的值都增加 val 。如果栈中元素总数小于 k ，则栈中的所有元素都增加 val 。
示例：
输入： ["CustomStack","push","push","pop","push","push","push","increment","increment","pop","pop","pop","pop"] [[3],[1],[2],[],[2],[3],[4],[5,100],[2,100],[],[],[],[]] 输出： [null,null,null,2,null,null,null,null,null,103,202,201,-1] 解释： CustomStack customStack = new CustomStack(3); // 栈是空的 [] customStack.push(1); // 栈变为 [1] customStack.push(2); // 栈变为 [1, 2] customStack.pop(); // 返回 2 --> 返回栈顶值 2，栈变为 [1] customStack.push(2); // 栈变为 [1, 2] customStack.push(3); // 栈变为 [1, 2, 3] customStack.push(4); // 栈仍然是 [1, 2, 3]，不能添加其他元素使栈大小变为 4 customStack.increment(5, 100); // 栈变为 [101, 102, 103] customStack.increment(2, 100); // 栈变为 [201, 202, 103] customStack.pop(); // 返回 103 --> 返回栈顶值 103，栈变为 [201, 202] customStack.pop(); // 返回 202 --> 返回栈顶值 202，栈变为 [201] customStack.pop(); // 返回 201 --> 返回栈顶值 201，栈变为 [] customStack.pop(); // 返回 -1 --> 栈为空，返回 -1
提示：
1 <= maxSize <= 10001 <= x <= 10001 <= k <= 10000 <= val <= 100increment，push 以及 pop 分别最多调用 1000 次原站题解
golang 解法, 执行用时: 24 ms, 内存消耗: 6.8 MB, 提交时间: 2022-11-19 18:25:04
type CustomStack struct {
maxLen int
arr []int
}
func Constructor(maxSize int) CustomStack {
cs := CustomStack{
maxLen: maxSize,
arr: make([]int, 0),
}
return cs
}
func (this *CustomStack) Push(x int) {
if len(this.arr) < this.maxLen {
this.arr = append(this.arr, x)
}
}
func (this *CustomStack) Pop() int {
if len(this.arr) == 0 {
return -1
}
num := this.arr[len(this.arr)-1]
this.arr = this.arr[:len(this.arr)-1]
return num
}
func (this *CustomStack) Increment(k int, val int) {
if len(this.arr) <= k {
for i := 0; i < len(this.arr);i++ {
this.arr[i] += val
}
} else {
for i := 0; i < k;i++ {
this.arr[i] += val
}
}
}
/**
* Your CustomStack object will be instantiated and called as such:
* obj := Constructor(maxSize);
* obj.Push(x);
* param_2 := obj.Pop();
* obj.Increment(k,val);
*/
python3 解法, 执行用时: 72 ms, 内存消耗: 15.9 MB, 提交时间: 2022-11-19 18:24:30
class CustomStack:
def __init__(self, maxSize: int):
self.stk = [0] * maxSize
self.add = [0] * maxSize
self.top = -1
def push(self, x: int) -> None:
if self.top != len(self.stk) - 1:
self.top += 1
self.stk[self.top] = x
def pop(self) -> int:
if self.top == -1:
return -1
ret = self.stk[self.top] + self.add[self.top]
if self.top != 0:
self.add[self.top - 1] += self.add[self.top]
self.add[self.top] = 0
self.top -= 1
return ret
def increment(self, k: int, val: int) -> None:
lim = min(k - 1, self.top)
if lim >= 0:
self.add[lim] += val
# Your CustomStack object will be instantiated and called as such:
# obj = CustomStack(maxSize)
# obj.push(x)
# param_2 = obj.pop()
# obj.increment(k,val)
python3 解法, 执行用时: 104 ms, 内存消耗: 15.9 MB, 提交时间: 2022-11-19 18:24:14
class CustomStack:
def __init__(self, maxSize: int):
self.stk = [0] * maxSize
self.top = -1
def push(self, x: int) -> None:
if self.top != len(self.stk) - 1:
self.top += 1
self.stk[self.top] = x
def pop(self) -> int:
if self.top == -1:
return -1
self.top -= 1
return self.stk[self.top + 1]
def increment(self, k: int, val: int) -> None:
lim = min(k, self.top + 1)
for i in range(lim):
self.stk[i] += val
# Your CustomStack object will be instantiated and called as such:
# obj = CustomStack(maxSize)
# obj.push(x)
# param_2 = obj.pop()
# obj.increment(k,val)