(java)Maximum Subarray

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

.

思路:还是典型的贪心，设置一个maxsum和sum，循环遍历这个数组，当maxsum <sum时，maxsum=sum；

当sum<0 时，将前面的丢弃，sum=0，重新开始；

注意边界nums[i]都是小于0的，返回那个最大的数。

代码如下(已通过leetcode)

public class Solution {

public int maxSubArray(int[] nums) {

boolean flag=true;

int j=0;

int temp=-Integer.MIN_VALUE;

while(j<nums.length){

if(nums[j]>0){

flag=false;

break;

}

if(nums[j]>temp) temp=nums[j];

j++;

}

if(flag) return temp;

int sum=0;

int maxsum=0;

for(int i=0;i<nums.length;i++){

sum=sum+nums[i];

if(sum>maxsum) maxsum=sum;

if(sum<0) sum=0;

}

return maxsum;

}

}