[LeetCode] 901. Online Stock Span

最新推荐文章于 2024-08-18 09:06:00 发布

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最新推荐文章于 2024-08-18 09:06:00 发布

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分类专栏： LeetCode

本文链接：https://blog.youkuaiyun.com/u013383813/article/details/85679988

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本文详细解析了LeetCode上的在线股票跨度问题，介绍了一种使用栈数据结构的高效解决方案，通过维护一个特殊的数据结构来快速计算当前元素的跨度，即最长连续子序列长度，其中所有元素都不大于当前元素。

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题：https://leetcode.com/problems/online-stock-span/

题目大意

不断给出元素，求当前元素开始往前的最大子串，且串中每个元素的值都小于等于该元素。

思路

class stockPair{
    int price;
    int day;
    public stockPair(int price,int day){
        this.price = price;
        this.day = day;
    }
}

class StockSpanner {
    Stack<stockPair> stack;
    int day;
    public StockSpanner() {
        stack = new Stack<>();
        day = 0;
    }
    
    public int next(int price) {
        day++;
        while(!stack.isEmpty() && stack.peek().price <= price){
            stack.pop();
        }
        int res;
        if(stack.isEmpty())
            res= day;
        else
            res =day - stack.peek().day;
        stack.add(new stockPair(price,day));
        return res;   
    }
}

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

class StockSpanner {
    Stack<int[]> stack = new Stack<>();

    public StockSpanner() {
    }

    public int next(int price) {
        int res = 1;
        while (!stack.isEmpty() && stack.peek()[0] <= price)
            res += stack.pop()[1];
        stack.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);
 */