HDU 1231 最大连续子序列

Posted 2020-09-12 Lorazepam

http://acm.hdu.edu.cn/showproblem.php?pid=1231

Dp[i] 以a[i]元素结尾的子序列的最大和

记录 再记录一下起始位置即可

 1 #include <iostream>
 2 #include <string.h>
 3 #include <stdio.h>
 4 using namespace std;
 5 
 6 int a[10007];
 7 int dp[10007];
 8 int st[10007];
 9 int main()
10 {
11     int n;
12     while(cin >> n)
13     {
14         bool neg = true;
15         if (!n) break;
16         memset(dp, 0 ,sizeof(dp));
17         for (int i = 0; i < n; i++)
18         {
19             scanf("%d", &a[i]);
20             if (a[i] >= 0) neg = false;
21         }
22         if (neg)
23         {
24             cout << 0 << " " << a[0] << " " << a[n-1] << endl;
25             continue;
26         }
27         dp[0] = a[0];
28         st[0] = 0;
29         for (int i = 1; i < n; i++)
30         {
31             if (dp[i-1]+a[i] > a[i])
32             {
33                 dp[i] = dp[i-1]+a[i];
34                 st[i] = st[i-1];
35             }
36             else
37             {
38                 dp[i] = a[i];
39                 st[i] = i;
40             }
41         }
42         int ans = -1e9;
43         int index = 0;
44         for (int i = 0; i < n; i++)
45         {
46             if(ans < dp[i])
47             {
48                 index = i;
49                 ans = dp[i];
50             }
51         }
52         cout << ans << " " << a[st[index]] << " " << a[index] << endl;
53     }
54     return 0;
55 }