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

.

click to show more practice.

More practice:
If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.
题意：求数组中和最大的连续序列
思路：max（n） = max{ max(n-1), sum+a
}, 其中sum表示连续到n的非负片段和（即：若sum<0,则sum从0开始计数）。

class Solution {
public:
int maxSubArray(vector<int>& nums) {
if (nums.size() < 1)
return 0;
int maxNum = (numeric_limits<int>::min)();
int sum = 0;
for (int i = 0; i < nums.size(); i++){
sum += nums[i];
if (sum > maxNum)
maxNum = sum;
if (sum < 0){
sum = 0;
}
}
return maxNum;
}
};