Description

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Example:

Input: [-,,-,,-,,,-,],
Output:
Explanation: [,-,,] has the largest sum = .

Follow up:

If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

我的解法:两层循环 第一层循环通过i控制进度,第二层循环计算从i 开始的子数组的和的最大值

C#版解法:

public class Solution {
public int MaxSubArray(int[] nums) {
if(nums.Length == )
return ;
int max = int.MinValue;
for(int i = ; i < nums.Length; i++){
int tempSum=;
for(int j =i; j < nums.Length; j++){
tempSum += nums[j];
if(tempSum > max)
max = tempSum;
}
}
return max;
}
}

看题目描述,可以使用divide and conquer(分而治之)思想去实现,时间复杂度会大幅度降低:这里先将解法贴出来,具体的分而治之(动态规划)的学习放到下一个文章中

static int maxCrossingSum(int[] arr, int l,
int m, int h)
{
// Include elements on left of mid.
int sum = ;
int left_sum = int.MinValue;
for (int i = m; i >= l; i--)
{
sum = sum + arr[i];
if (sum > left_sum)
left_sum = sum;
} // Include elements on right of mid
sum = ;
int right_sum = int.MinValue; ;
for (int i = m + ; i <= h; i++)
{
sum = sum + arr[i];
if (sum > right_sum)
right_sum = sum;
} // Return sum of elements on left
// and right of mid
return left_sum + right_sum;
} // Returns sum of maxium sum subarray
// in aa[l..h]
static int maxSubArraySum(int[] arr, int l,
int h)
{ // Base Case: Only one element
if (l == h)
return arr[l]; // Find middle point
int m = (l + h) / ; /* Return maximum of following three
possible cases:
a) Maximum subarray sum in left half
b) Maximum subarray sum in right half
c) Maximum subarray sum such that the
subarray crosses the midpoint */
return Math.Max(Math.Max(maxSubArraySum(arr, l, m),
maxSubArraySum(arr, m + , h)),
maxCrossingSum(arr, l, m, h));
} /* Driver program to test maxSubArraySum */
public static void Main()
{
int[] arr = { -, , , -, };
int n = arr.Length;
int max_sum = maxSubArraySum(arr, , n - ); Console.Write("Maximum contiguous sum is " +
max_sum);
Console.ReadKey();
}

分而治之的链接:算法学习 分而治之思想

LeetCode Array Easy 53. Maximum Subarray 个人解法 和分治思想的学习的更多相关文章

  1. LeetCode练题——53. Maximum Subarray

    1.题目 53. Maximum Subarray——Easy Given an integer array nums, find the contiguous subarray (containin ...

  2. [LeetCode&Python] Problem 53. Maximum Subarray

    Given an integer array nums, find the contiguous subarray (containing at least one number) which has ...

  3. [array] leetcode - 53. Maximum Subarray - Easy

    leetcode - 53. Maximum Subarray - Easy descrition Find the contiguous subarray within an array (cont ...

  4. Leetcode之53. Maximum Subarray Easy

    Leetcode 53 Maximum Subarray Easyhttps://leetcode.com/problems/maximum-subarray/Given an integer arr ...

  5. [Leetcode][Python]53: Maximum Subarray

    # -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 53: Maximum Subarrayhttps://leetcode.co ...

  6. 53. Maximum Subarray【leetcode】

    53. Maximum Subarray[leetcode] Find the contiguous subarray within an array (containing at least one ...

  7. Leetcode#53.Maximum Subarray(最大子序和)

    题目描述 给定一个序列(至少含有 1 个数),从该序列中寻找一个连续的子序列,使得子序列的和最大. 例如,给定序列 [-2,1,-3,4,-1,2,1,-5,4], 连续子序列 [4,-1,2,1] ...

  8. 小旭讲解 LeetCode 53. Maximum Subarray 动态规划 分治策略

    原题 Given an integer array nums, find the contiguous subarray (containing at least one number) which ...

  9. 41. leetcode 53. Maximum Subarray

    53. Maximum Subarray Find the contiguous subarray within an array (containing at least one number) w ...

随机推荐

  1. aiohttp上报:Got more than 8190 bytes (10160) when reading Status line is too long.错误的解决办法

    通过浏览器向web服务传递base64码的图片时遇到参数过长的问题? 解决办法:查看aiohttp的源码:aiohttp/http_parser.py下找到: class HeadersParser: ...

  2. notepad++编辑软件

    官网:http://notepad-plus-plus.org/ 官网截图(2015/4/29): 版本: Notepad++ 6.7.7 下载地址:http://notepad-plus-plus. ...

  3. Java compiler level does not match the version of the installed Java project facet错误

    出现问题情景:从其他地方导入一个项目的时候报错:Java compiler level does not match the version of the installed Java project ...

  4. 【记录】Redis 基础

    Redis可以存放五种类型 1:String(字符串) 2:List(列表) 3:Hash(字典) 4:Set(集合) 5:ZSet(有序集合) String (字符串) redis 127.0.0. ...

  5. Codeforces 1195E OpenStreetMap 单调队列套单调队列

    题意:给你一个n * m的矩阵,问所有的a * b的子矩阵的最小的元素的和是多少.题目给出了矩阵中的数的数据生成器. 思路:如果这个问题是1维的,即求所有区间的最小元素的和,用单调队列O(n)就可以做 ...

  6. C++ 虚函数和多重继承的内存布局初探

    C++ 对象的内存布局 一切以事实说话: 代码: 1: #include <stdio.h> 2:  3: class A { 4: public: 5: int a; 6: int b; ...

  7. jsp获取url路径的方法

    如果你请求的URL是  http://localhost:8080/demo/Index.jsp request.getScheme() //输出:http request.getServerName ...

  8. JavaSE---多线程---线程的创建、启动

    1.概述 1.1 Java中使用Thread类表示线程:   所有的线程对象必须是Thread类 或 其子类的实例:   每条线程的作用:完成一定的任务:   Java中使用run方法来封装线程执行体 ...

  9. v-bin:href 绑定链接

    <div id="app06"> <a v-bind:href="URL">我是百度</a> </div> 调用 ...

  10. POJ 1273 Drainage Ditches (网络流Dinic模板)

    Description Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover ...