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1381. Design a Stack With Increment Operation

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Description

Design a stack which supports the following operations.

Implement the CustomStack class:

• CustomStack(int maxSize) Initializes the object with maxSize which is the maximum number of elements in the stack or do nothing if the stack reached the maxSize.
• void push(int x) Adds x to the top of the stack if the stack hasn't reached the maxSize.
• int pop() Pops and returns the top of stack or -1 if the stack is empty.
• void inc(int k, int val) Increments the bottom k elements of the stack by val. If there are less than k elements in the stack, just increment all the elements in the stack.

 

Example 1:

Input
["CustomStack","push","push","pop","push","push","push","increment","increment","pop","pop","pop","pop"]
[[3],[1],[2],[],[2],[3],[4],[5,100],[2,100],[],[],[],[]]
Output
[null,null,null,2,null,null,null,null,null,103,202,201,-1]
Explanation
CustomStack customStack = new CustomStack(3); // Stack is Empty []
customStack.push(1);                          // stack becomes [1]
customStack.push(2);                          // stack becomes [1, 2]
customStack.pop();                            // return 2 --> Return top of the stack 2, stack becomes [1]
customStack.push(2);                          // stack becomes [1, 2]
customStack.push(3);                          // stack becomes [1, 2, 3]
customStack.push(4);                          // stack still [1, 2, 3], Don't add another elements as size is 4
customStack.increment(5, 100);                // stack becomes [101, 102, 103]
customStack.increment(2, 100);                // stack becomes [201, 202, 103]
customStack.pop();                            // return 103 --> Return top of the stack 103, stack becomes [201, 202]
customStack.pop();                            // return 202 --> Return top of the stack 102, stack becomes [201]
customStack.pop();                            // return 201 --> Return top of the stack 101, stack becomes []
customStack.pop();                            // return -1 --> Stack is empty return -1.

 

Constraints:

• 1 <= maxSize <= 1000
• 1 <= x <= 1000
• 1 <= k <= 1000
• 0 <= val <= 100
• At most 1000 calls will be made to each method of increment, push and pop each separately.

Solutions

Python3

class CustomStack:
    def __init__(self, maxSize: int):
        self.s = [0] * maxSize
        self.t = 0

    def push(self, x: int) -> None:
        if self.t < len(self.s):
            self.s[self.t] = x
            self.t += 1

    def pop(self) -> int:
        if self.t == 0:
            return -1
        self.t -= 1
        return self.s[self.t]

    def increment(self, k: int, val: int) -> None:
        for i in range(min(k, self.t)):
            self.s[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)

Java

class CustomStack {
    private int[] s;
    private int t;

    public CustomStack(int maxSize) {
        s = new int[maxSize];
    }

    public void push(int x) {
        if (t < s.length) {
            s[t++] = x;
        }
    }

    public int pop() {
        return t == 0 ? -1 : s[--t];
    }

    public void increment(int k, int val) {
        for (int i = 0; i < Math.min(k, t); ++i) {
            s[i] += 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);
 */

TypeScript

class CustomStack {
    maxSize: number;
    size: number;
    stack: Array<number>;
    constructor(maxSize: number) {
        this.maxSize = maxSize;
        this.size = 0;
        this.stack = [];
    }

    push(x: number): void {
        if (this.size >= this.maxSize) return;
        this.size++;
        this.stack.unshift(x);
    }

    pop(): number {
        if (!this.size) return -1;
        this.size--;
        return this.stack.shift();
    }

    increment(k: number, val: number): void {
        for (let i = Math.max(this.size - k, 0); i < this.size; i++) {
            this.stack[i] = this.stack[i] + 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)
 */

C++

class CustomStack {
public:
    vector<int> s;
    int t;

    CustomStack(int maxSize) {
        s.resize(maxSize);
        t = 0;
    }

    void push(int x) {
        if (t < s.size()) s[t++] = x;
    }

    int pop() {
        return t == 0 ? -1 : s[--t];
    }

    void increment(int k, int val) {
        for (int i = 0; i < min(k, t); ++i) s[i] += 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);
 */

Go

type CustomStack struct {
	s []int
	t int
}

func Constructor(maxSize int) CustomStack {
	s := make([]int, maxSize)
	return CustomStack{s, 0}
}

func (this *CustomStack) Push(x int) {
	if this.t < len(this.s) {
		this.s[this.t] = x
		this.t++
	}
}

func (this *CustomStack) Pop() int {
	if this.t == 0 {
		return -1
	}
	this.t--
	return this.s[this.t]
}

func (this *CustomStack) Increment(k int, val int) {
	for i := 0; i < k && i < this.t; i++ {
		this.s[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);
 */

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