1 #define pb push_back
 2 #define _for(i,a,b) for(int i = (a);i < (b);i ++)
 3 const int maxn = 50003;
 4 
 5 class Solution
 6 {
 7     public:
 8         int largestSumAfterKNegations(vector<int>& A, int K)
 9         {
10             int hash[202] {0};
11             int fnum = 0
 
;
12             _for(i,0,A.size())
13             {
14                 if(A[i]<0)
15                     fnum ++;
16                 hash[A[i]+100] ++;
17             } 
18             if(fnum<=K)
19             {
20                 
21                 _for(i,0,100)
22                 {
23
 
                     hash[200-i] += hash[i];
24                     hash[i] = 0; 
25                 }
26                 K -= fnum;
27                 
28                 if(K&0x1)
29                 {
30                     _for(i,100,201)
31                     {
32                         if
 
(hash[i])
33                         {
34                             hash[200-i]++;
35                             hash[i] --;
36                             break;
37                         }
38                     }
39                 }
40             }
41             else
42             {
43                 int index = 0;
44                 while(K --)
45                 {
46                     while(hash[index]==0)
47                         index ++;
48                     hash[index] --;
49                     hash[200-index] ++; 
50                 }
51             }
52 
53             int rnt = 0;
54             _for(i,0,201)
55             {
56                 rnt += hash[i] * (i-100);
57             }
58             return rnt;
59         }
60 };

分類討論，隨便亂搞過了

Leetcode-1005 Maximize Sum Of Array After K Negations(K 次取反後最大化的數組和)