LeetCode 53. 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

.

1、该题求连续子串最大和。

2、用Max[i]表示以i结尾的连续子串最大和，因此Max[i]只与Max[i - 1]有关。

3、当Max[i - 1] > 0时，Max[i] = Max[i - 1] + nums[i]，当Max[i - 1] <= 0时，Max[i] = nums[i]。

Java代码如下所示：

public class Solution {
public int maxSubArray(int[] nums) {
if(nums == null || nums.length == 0) {
return 0;
}
int[] Max = new int[nums.length];
int result;
Max[0] = result = nums[0];
for(int i = 1; i < nums.length; i++) {
if(Max[i - 1] > 0) {
Max[i] = Max[i - 1] + nums[i];
} else {
Max[i] = nums[i];
}
if(result < Max[i]) {
result = Max[i];
}
}
return result;
}

public static void main(String[] args) {
int[] nums = {-2,1,-3,4,-1,2,1,-5,4};
Solution solution = new Solution();
System.out.println(solution.maxSubArray(nums));
}
}