LeetCode Maximum Subarray

Description:

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

.
Solution:

这道题目是很经典的题目了

求最大区间和

先判断是否都是负的，如果是取最大的

否则，进行累加。当目前累加的结果小于0的时候，重新累加。

累加过程中维护最大值。

public class Solution {
public int maxSubArray(int[] nums) {
int max = aboveZero(nums);
if (max <= 0)
return max;

int temp = 0;
for (int i = 0; i < nums.length; i++) {
if (temp + nums[i] < 0) {
temp = 0;
} else
temp += nums[i];
max = Math.max(max, temp);
}
max = Math.max(max, temp);

return max;
}

public int aboveZero(int[] nums) {
int max = nums[0];
for (int i : nums) {
if (i > 0)
return i;
else
max = Math.max(max, i);
}
return max;
}
}