# 53. Maximum Subarray

## 1.問題 

* 給予一個整數的array, 找出總和為最大值的連續subarray

![](https://901207480-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LGKoChvN9am4__HCIRK%2F-LN__HFQDfXcoazCKNt7%2F-LN__KSpXhFSXikIO-N7%2F%E8%9E%A2%E5%B9%95%E5%BF%AB%E7%85%A7%202018-09-29%20%E4%B8%8B%E5%8D%889.46.53.png?alt=media\&token=e09d19e1-3052-4f02-8227-f988a6081b00)

## 2.想法 <a href="#id-2-xiang-fa" id="id-2-xiang-fa"></a>

* 提問
  * 確認題意:  取得最大總和的subarray
* parameter
  * number list
* test input
* 說明想法
  * 由左邊開始移動, 計算subarray的總和
  * 記錄歷史的最大總和
  * 一旦總和小於0, 則讓總和歸零
* 測試計算複雜度

## **3.程式碼** <a href="#id-3-cheng-shi" id="id-3-cheng-shi"></a>

```
class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int ans = nums[0], i, j, sum=0;
        for(i = 0;i< (int)nums.size(); i++){
            sum += nums[i];
            ans = max(sum,ans);
            sum = max(sum,0);
        }
        return ans;
    }
};
```


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