zoukankan      html  css  js  c++  java
  • 【数组】Best Time to Buy and Sell Stock I/II

    Best Time to Buy and Sell Stock I

    题目:

    Say you have an array for which the ith element is the price of a given stock on day i.

    If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

    思路:

    只需要找出最大的差值即可,即 max(prices[j] – prices[i]) ,i < j。一次遍历即可,在遍历的时间用遍历low记录 prices[o....i] 中的最小值,就是当前为止的最低售价,时间复杂度为 O(n)。

    /**
     * @param {number[]} prices
     * @return {number}
     */
    var maxProfit = function(prices) {
        if(prices.length==0){
            return 0;
        }
        var n=prices.length,low=2147483647,ans=0;
        for(var i=0;i<n;i++){
            if(prices[i]<low){
                low=prices[i];
            }else if(prices[i]-low>ans){
                ans=prices[i]-low;
            }
        }
        
        return ans;
    };

    Best Time to Buy and Sell Stock I

    题目:

    Say you have an array for which the ith element is the price of a given stock on day i.

    Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

    思路:

    此题和上面一题的不同之处在于不限制交易次数。也是一次遍历即可,只要可以赚就做交易。

    /**
     * @param {number[]} prices
     * @return {number}
     */
    var maxProfit = function(prices) {
        var n=prices.length,res=0;
        
        if(n==0){
            return 0;
        }
    
        for(var i=1;i<n;i++){
            if(prices[i]>prices[i-1]){
                res+=prices[i]-prices[i-1]
            }
        }
        
        return res;
    };
  • 相关阅读:
    iOS-25个小技巧
    iOS-UITableView的使用
    iOS-UIPickerView
    iOS-UIStoryboard和UIResponder
    javascript弹出层-DEMO001
    jQuery源码分析-02正则表达式-RegExp-常用正则表达式
    JSON动态生成树
    回顾码农历程总结2013 期待2014
    大数据量分页存储过程效率测试附代码
    关于对象序列化json 说说
  • 原文地址:https://www.cnblogs.com/shytong/p/5134809.html
Copyright © 2011-2022 走看看