//YOUTUBE:youtube.com/channel/UCctCQUpRrxYnCBT7Yh2TuAA
//soicodoc10tin
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define reset(x) memset(x, 0,sizeof(x))
#define Rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define For(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define Ford(i,l,u) for(int (i)=(int)(l);(i)>=(int)(u);--(i))
#define MIN(x,y) if (x > (y)) x = (y)
#define MAX(x,y) if (x < (y)) x = (y)
#define PB push_back
#define mp make_pair
#define F first
#define S second
#define maxn 1000006
#define MOD 1000000007
#define remain(x) if (x > MOD) x -= MOD
#define pii pair<int, int>
#define bit(x, i) (((x) >> (i)) & 1)
#define LG 30
#define Task "a"
#define int long long
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
 
int dx[] = {0 , -1 , 1 , 0};
int dy[] = {-1 , 0 , 0 , 1};
 
int n , a[maxn] , dp[maxn][2];
 
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    if(fopen(Task".inp" , "r")){
        freopen(Task".inp" , "r" , stdin);
        freopen(Task".out" , "w" , stdout);
    }
    cin >> n;
    For(i , 1 , n) cin >> a[i];
    dp[1][0] = 0;
    dp[1][1] = a[1];
    For(i , 2 , n){
        dp[i][0] = max(dp[i - 1][1] - a[i] , dp[i - 1][0]);
        dp[i][1] = max(dp[i - 1][0] + a[i] , dp[i - 1][1]);
    }
    cout << max(dp[n][0] , dp[n][1]);
    return 0;
}
 

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

Nwo0IDkgMiA0IDEgMyA3

7
4 9 2 4 1 3 7