CUBE-006: C-Value

#include <bits/stdc++.h>

using namespace std;
using lli = long long;
const lli INF = 2e18;

int n;
lli dp[2][3];

int main(){

    scanf("%d", &n);

    for(int i = 1; i <= n; i ++) {
        lli x;
        scanf("%lld", &x);
        for(int cnt = 2; cnt >= 0; cnt --){
            if((cnt%2 == 0 and i%2 == 1) or (cnt%2 == 1 and i%2 == 0))
                dp[i%2][cnt] = dp[(i-1)%2][cnt] - x;
            else
                dp[i%2][cnt] = dp[(i-1)%2][cnt] + x;
            if(cnt < 2) dp[i%2][cnt] = min(dp[i%2][cnt], dp[i%2][cnt+1]);
        }
    }

    printf("%lld", dp[n%2][0]);

    return 0;
}