CF789C. Functions again

/*
 CF789C. Functions again
 http://codeforces.com/contest/789/problem/C
 水题
 题意：求数组中的连续和的最大值
 */
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
//#define test
using namespace std;
const int Nmax=1e6;
int num[Nmax];
int num1[Nmax];
int num2[Nmax];
long long ans1,ans2;
int main()
{
    #ifdef test
    #endif
    int n;
    //freopen("test.in","r",stdin);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&num[i]);
    }
    for(int i=1;i<n;i++)
        num[i]=abs(num[i]-num[i+1]);
    for(int i=1;i<n;i++)
    {
        if(i&1)
            num1[i]=num[i],num2[i]=-num[i];
        else
            num1[i]=-num[i],num2[i]=num[i];
    }
    //for(int i=1;i<n;i++)
        //printf("%d %d
",num1[i],num2[i]);
    ans1=ans2=0LL;
    long long tmp=0LL;
    for(int i=1;i<n;i++)
    {
        tmp+=1LL*num1[i];
        if(tmp>ans1)
            ans1=tmp;
        if(tmp<0LL)
            tmp=0LL;
    }
    tmp=0;
    for(int i=1;i<n;i++)
    {
        tmp+=1LL*num2[i];
        //printf("i:%d tmp:%d
",i,tmp);
        if(tmp>ans2)
            ans2=tmp;
        if(tmp<0LL)
            tmp=0LL;
    }
    printf("%lld
",max(ans1,ans2));
    return 0;
}