| comments | difficulty | edit_url | rating | source | tags | |||
|---|---|---|---|---|---|---|---|---|
true |
中等 |
1285 |
第 180 场周赛 Q2 |
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请你设计一个支持对其元素进行增量操作的栈。
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。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 stk = new CustomStack(3); // 栈是空的 [] stk.push(1); // 栈变为 [1] stk.push(2); // 栈变为 [1, 2] stk.pop(); // 返回 2 --> 返回栈顶值 2，栈变为 [1] stk.push(2); // 栈变为 [1, 2] stk.push(3); // 栈变为 [1, 2, 3] stk.push(4); // 栈仍然是 [1, 2, 3]，不能添加其他元素使栈大小变为 4 stk.increment(5, 100); // 栈变为 [101, 102, 103] stk.increment(2, 100); // 栈变为 [201, 202, 103] stk.pop(); // 返回 103 --> 返回栈顶值 103，栈变为 [201, 202] stk.pop(); // 返回 202 --> 返回栈顶值 202，栈变为 [201] stk.pop(); // 返回 201 --> 返回栈顶值 201，栈变为 [] stk.pop(); // 返回 -1 --> 栈为空，返回 -1
提示：
1 <= maxSize, x, k <= 10000 <= val <= 100- 每种方法
increment，push以及pop分别最多调用1000次
我们可以用一个数组
调用
调用
调用
时间复杂度
class CustomStack:
def __init__(self, maxSize: int):
self.stk = [0] * maxSize
self.add = [0] * maxSize
self.i = 0
def push(self, x: int) -> None:
if self.i < len(self.stk):
self.stk[self.i] = x
self.i += 1
def pop(self) -> int:
if self.i <= 0:
return -1
self.i -= 1
ans = self.stk[self.i] + self.add[self.i]
if self.i > 0:
self.add[self.i - 1] += self.add[self.i]
self.add[self.i] = 0
return ans
def increment(self, k: int, val: int) -> None:
i = min(k, self.i) - 1
if i >= 0:
self.add[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)class CustomStack {
private int[] stk;
private int[] add;
private int i;
public CustomStack(int maxSize) {
stk = new int[maxSize];
add = new int[maxSize];
}
public void push(int x) {
if (i < stk.length) {
stk[i++] = x;
}
}
public int pop() {
if (i <= 0) {
return -1;
}
int ans = stk[--i] + add[i];
if (i > 0) {
add[i - 1] += add[i];
}
add[i] = 0;
return ans;
}
public void increment(int k, int val) {
if (i > 0) {
add[Math.min(i, k) - 1] += val;
}
}
}
/**
* Your CustomStack object will be instantiated and called as such:
* CustomStack obj = new CustomStack(maxSize);
* obj.push(x);
* int param_2 = obj.pop();
* obj.increment(k,val);
*/class CustomStack {
public:
CustomStack(int maxSize) {
stk.resize(maxSize);
add.resize(maxSize);
i = 0;
}
void push(int x) {
if (i < stk.size()) {
stk[i++] = x;
}
}
int pop() {
if (i <= 0) {
return -1;
}
int ans = stk[--i] + add[i];
if (i > 0) {
add[i - 1] += add[i];
}
add[i] = 0;
return ans;
}
void increment(int k, int val) {
if (i > 0) {
add[min(k, i) - 1] += val;
}
}
private:
vector<int> stk;
vector<int> add;
int i;
};
/**
* Your CustomStack object will be instantiated and called as such:
* CustomStack* obj = new CustomStack(maxSize);
* obj->push(x);
* int param_2 = obj->pop();
* obj->increment(k,val);
*/type CustomStack struct {
stk []int
add []int
i int
}
func Constructor(maxSize int) CustomStack {
return CustomStack{make([]int, maxSize), make([]int, maxSize), 0}
}
func (this *CustomStack) Push(x int) {
if this.i < len(this.stk) {
this.stk[this.i] = x
this.i++
}
}
func (this *CustomStack) Pop() int {
if this.i <= 0 {
return -1
}
this.i--
ans := this.stk[this.i] + this.add[this.i]
if this.i > 0 {
this.add[this.i-1] += this.add[this.i]
}
this.add[this.i] = 0
return ans
}
func (this *CustomStack) Increment(k int, val int) {
if this.i > 0 {
this.add[min(k, this.i)-1] += 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);
*/class CustomStack {
private stk: number[];
private add: number[];
private i: number;
constructor(maxSize: number) {
this.stk = Array(maxSize).fill(0);
this.add = Array(maxSize).fill(0);
this.i = 0;
}
push(x: number): void {
if (this.i < this.stk.length) {
this.stk[this.i++] = x;
}
}
pop(): number {
if (this.i <= 0) {
return -1;
}
const ans = this.stk[--this.i] + this.add[this.i];
if (this.i > 0) {
this.add[this.i - 1] += this.add[this.i];
}
this.add[this.i] = 0;
return ans;
}
increment(k: number, val: number): void {
if (this.i > 0) {
this.add[Math.min(this.i, k) - 1] += val;
}
}
}
/**
* Your CustomStack object will be instantiated and called as such:
* var obj = new CustomStack(maxSize)
* obj.push(x)
* var param_2 = obj.pop()
* obj.increment(k,val)
*/