1883E - Look Back - CodeForces Solution

// author: rshohruh
// create time: Oct 22 2023, 17:14


#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
const int MOD = 1e9+7;
const int inf = 1e9;
#define endl "\n"

int dx[] = {0, 0, -1, 1};
int dy[] = {-1, 1, 0, 0};

#define with_testcases
void t_main(){
    int n;
    cin >> n;
    vector<int> a(n);
    for(int &x: a) cin >> x;
    ll ans = 0, cur = 0;
    for(int i = 1; i < n; ++i){
        int x = a[i], y = a[i-1];
        ll res = 0;
        if(x < y) {
            while(x < y){
                x *= 2;
                res ++;
            }
        } else{
            x = a[i], y = a[i-1];
            while(y*2 <= x){
                y *= 2;
                res --;
            }
        }
        cur = max(cur+res, 0LL);
        ans += cur;
    }
    cout << ans;
}

signed main(){
    signed t = 1;
    cin.tie(nullptr)->sync_with_stdio(false);
    #ifdef with_testcases
        cin >> t;
    #endif
    while(t--){
        t_main();
        cout << '\n';
    }
    return 0;
}


/*
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██████╔╝███████╗███████║██║   ██║███████║██████╔╝██║   ██║███████║
██╔══██╗╚════██║██╔══██║██║   ██║██╔══██║██╔══██╗██║   ██║██╔══██║
██║  ██║███████║██║  ██║╚██████╔╝██║  ██║██║  ██║╚██████╔╝██║  ██║
╚═╝  ╚═╝╚══════╝╚═╝  ╚═╝ ╚═════╝ ╚═╝  ╚═╝╚═╝  ╚═╝ ╚═════╝ ╚═╝  ╚═╝
*/