CF789C. Functions again 

 1 /*
 2  CF789C. Functions again
 3  http://codeforces.com/contest/789/problem/C
 4  水题
 5  题意：求数组中的连续和的最大值
 6  */
 7 #include <cstdio>
 8 #include <algorithm>
 9 #include <cstring>
10 #include <cmath>
11 #include <vector>
12 #include <queue>
13 //#define test
14 using namespace std;
15 const int Nmax=1e6;
16 int num[Nmax];
17 int num1[Nmax];
18 int num2[Nmax];
19 long long ans1,ans2;
20 int main()
21 {
22     #ifdef test
23     #endif
24     int n;
25     //freopen("test.in","r",stdin);
26     scanf("%d",&n);
27     for(int i=1;i<=n;i++)
28     {
29         scanf("%d",&num[i]);
30     }
31     for(int i=1;i<n;i++)
32         num[i]=abs(num[i]-num[i+1]);
33     for(int i=1;i<n;i++)
34     {
35         if(i&1)
36             num1[i]=num[i],num2[i]=-num[i];
37         else
38             num1[i]=-num[i],num2[i]=num[i];
39     }
40     //for(int i=1;i<n;i++)
41         //printf("%d %d\n",num1[i],num2[i]);
42     ans1=ans2=0LL;
43     long long tmp=0LL;
44     for(int i=1;i<n;i++)
45     {
46         tmp+=1LL*num1[i];
47         if(tmp>ans1)
48             ans1=tmp;
49         if(tmp<0LL)
50             tmp=0LL;
51     }
52     tmp=0;
53     for(int i=1;i<n;i++)
54     {
55         tmp+=1LL*num2[i];
56         //printf("i:%d tmp:%d\n",i,tmp);
57         if(tmp>ans2)
58             ans2=tmp;
59         if(tmp<0LL)
60             tmp=0LL;
61     }
62     printf("%lld\n",max(ans1,ans2));
63     return 0;
64 }

 

posted @ 2017-03-30 11:55  BBBob  阅读(538)  评论(0)    收藏  举报