Leetcode刷题记——53. Maximum Subarray(最大子串)

一、题目叙述：

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array 

[-2,1,-3,4,-1,2,1,-5,4]

,

the contiguous subarray 

[4,-1,2,1]

 has the largest sum = 

6

.

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二、解题思路：

easy题！感觉算比较经典的求最大字串和的题思路如下：

（1）首先找出数组中最大的值（以防数组中全是负数，越加越小）作为max值。

（2）遍历数组，用sum来计算子串和 1、若子串和为负数，那么将sum值重置为0（因为负数必定带来的是缩小和的影响），继续向后遍历数组；2、若sum值不小于0，比较其与max值的大小，若大于，更新max值，继续遍历数组。

三、源码：

public class Solution
{
public int maxSubArray(int[] nums)
{
int max = Integer.MIN_VALUE;
int sum = 0;
for (int i = 0; i < nums.length; i ++)
{
if (max < nums[i]) max = nums[i];
}
for (int i = 0; i < nums.length; i++)
{
sum += nums[i];
if (sum < 0) sum = 0;
else
{
if (sum > max) max = sum;
}
}
return max;
}
public static void main(String args[])
{

// int[] digits = {0};
Solution solution = new Solution();
int[] abc = {2};
// int[] b = {2,3,4};
// for(int i = 0; i < abc.length; i ++)

System.out.print(solution.maxSubArray(abc));

}
}