README_EN.md

901. Online Stock Span

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Description

Design an algorithm that collects daily price quotes for some stock and returns the span of that stock's price for the current day.

The span of the stock's price today is defined as the maximum number of consecutive days (starting from today and going backward) for which the stock price was less than or equal to today's price.

• For example, if the price of a stock over the next 7 days were [100,80,60,70,60,75,85], then the stock spans would be [1,1,1,2,1,4,6].

Implement the StockSpanner class:

• StockSpanner() Initializes the object of the class.
• int next(int price) Returns the span of the stock's price given that today's price is price.

 

Example 1:

Input
["StockSpanner", "next", "next", "next", "next", "next", "next", "next"]
[[], [100], [80], [60], [70], [60], [75], [85]]
Output
[null, 1, 1, 1, 2, 1, 4, 6]

Explanation
StockSpanner stockSpanner = new StockSpanner();
stockSpanner.next(100); // return 1
stockSpanner.next(80);  // return 1
stockSpanner.next(60);  // return 1
stockSpanner.next(70);  // return 2
stockSpanner.next(60);  // return 1
stockSpanner.next(75);  // return 4, because the last 4 prices (including today's price of 75) were less than or equal to today's price.
stockSpanner.next(85);  // return 6

 

Constraints:

• 1 <= price <= 105
• At most 104 calls will be made to next.

Solutions

Python3

class StockSpanner:
    def __init__(self):
        self.stk = []

    def next(self, price: int) -> int:
        res = 1
        while self.stk and self.stk[-1][0] <= price:
            _, t = self.stk.pop()
            res += t
        self.stk.append([price, res])
        return res


# Your StockSpanner object will be instantiated and called as such:
# obj = StockSpanner()
# param_1 = obj.next(price)

Java

class StockSpanner {
    private Deque<int[]> stk;

    public StockSpanner() {
        stk = new ArrayDeque<>();
    }

    public int next(int price) {
        int res = 1;
        while (!stk.isEmpty() && stk.peek()[0] <= price) {
            int[] t = stk.pop();
            res += t[1];
        }
        stk.push(new int[]{price, res});
        return res;
    }
}

/**
 * Your StockSpanner object will be instantiated and called as such:
 * StockSpanner obj = new StockSpanner();
 * int param_1 = obj.next(price);
 */

TypeScript

class StockSpanner {
    stack: number[][];
    constructor() {
        this.stack = [];
    }

    next(price: number): number {
        let ans = 1;
        while (this.stack.length > 0 && this.stack[0][0] <= price) {
            let [p, c] = this.stack.shift();
            ans += c;
        }
        this.stack.unshift([price, ans]);
        return ans;
    }
}

/**
 * Your StockSpanner object will be instantiated and called as such:
 * var obj = new StockSpanner()
 * var param_1 = obj.next(price)
 */

C++

class StockSpanner {
public:
    stack<pair<int, int>> stk;

    StockSpanner() {
    }

    int next(int price) {
        int res = 1;
        while (!stk.empty() && stk.top().first <= price) {
            pair<int, int> t = stk.top();
            stk.pop();
            res += t.second;
        }
        stk.push({price, res});
        return res;
    }
};

/**
 * Your StockSpanner object will be instantiated and called as such:
 * StockSpanner* obj = new StockSpanner();
 * int param_1 = obj->next(price);
 */

Go

type StockSpanner struct {
	stk [][]int
}

func Constructor() StockSpanner {
	return StockSpanner{
		stk: make([][]int, 0),
	}
}

func (this *StockSpanner) Next(price int) int {
	res := 1
	for len(this.stk) > 0 && this.stk[len(this.stk)-1][0] <= price {
		t := this.stk[len(this.stk)-1]
		res += t[1]
		this.stk = this.stk[:len(this.stk)-1]
	}
	this.stk = append(this.stk, []int{price, res})
	return res
}

/**
 * Your StockSpanner object will be instantiated and called as such:
 * obj := Constructor();
 * param_1 := obj.Next(price);
 */

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