Problem: 2060D - Subtract Min Sort
Language: C++20 (GCC 13-64)

Previous submission (verdict: Wrong answer on test 2):
 /* Naman Gupta */

#include<bits/stdc++.h>

using namespace std;

 

#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)

#define MOD 1000000007

#define MOD1 998244353

#define INF 1e18

#define nline "\n"

#define pb push_back

#define ppb pop_back

#define mp make_pair

#define ff first

#define ss second

#define PI 3.141592653589793238462

#define set_bits __builtin_popcountll

#define sz(x) ((int)(x).size())

#define all(x) (x).begin(), (x).end()

 

#define ONLINE_JUDGE

#ifdef ONLINE_JUDGE

#define debug(x) cerr << #x<<" "; _print(x); cerr << endl;

#else

#define debug(x);

#endif

 

typedef long long ll;

typedef unsigned long long ull;

typedef long double lld;

typedef __int128 ell;

 

void _print(ll t) {cerr << t;}

void _print(int t) {cerr << t;}

void _print(string t) {cerr << t;}

void _print(char t) {cerr << t;}

void _print(lld t) {cerr << t;}

void _print(double t) {cerr << t;}

void _print(ull t) {cerr << t;}

 

template <class T, class V> void _print(pair <T, V> p);

template <class T> void _print(vector <T> v);

template <class T> void _print(set <T> v);

template <class T, class V> void _print(map <T, V> v);

template <class T> void _print(multiset <T> v);

template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}

template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

template <typename T> inline T Power(T a,T b){long long res=1;while(b>0){if(b&1){res=res*a;}a*=a;b>>=1;}return res;}

 

/*---------------------------------------------------------------------------------------------------------------------------*/

ll gcd(ll a, ll b) {if (b > a) {return gcd(b, a);} if (b == 0) {return a;} return gcd(b, a % b);}



ll expo(ll a, ll b, ll mod) {ll res = 1; while (b > 0) {if (b & 1)res = (res * a) % mod; a = (a * a) % mod; b = b >> 1;} return res;}

void extendgcd(ll a, ll b, ll*v) {if (b == 0) {v[0] = 1; v[1] = 0; v[2] = a; return ;} extendgcd(b, a % b, v); ll x = v[1]; v[1] = v[0] - v[1] * (a / b); v[0] = x; return;} //pass an arry of size1 3

ll mminv(ll a, ll b) {ll arr[3]; extendgcd(a, b, arr); return arr[0];} //for non prime b

ll mminvprime(ll a, ll b) {return expo(a, b - 2, b);}

bool revsort(ll a, ll b) {return a > b;}

ll combination(ll n, ll r, ll m, ll *fact, ll *ifact) {ll val1 = fact[n]; ll val2 = ifact[n - r]; ll val3 = ifact[r]; return (((val1 * val2) % m) * val3) % m;}

void google(int t) {cout << "Case #" << t << ": ";}

vector<ll> sieve(int n) {int*arr = new int[n + 1](); vector<ll> vect; for (int i = 2; i <= n; i++)if (arr[i] == 0) {vect.push_back(i); for (int j = 2 * i; j <= n; j += i)arr[j] = 1;} return vect;}

ll mod_add(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a + b) % m) + m) % m;}

ll mod_mul(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a * b) % m) + m) % m;}

ll mod_sub(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a - b) % m) + m) % m;}

ll mod_div(ll a, ll b, ll m) {a = a % m; b = b % m; return (mod_mul(a, mminvprime(b, m), m) + m) % m;}  //only for prime m

ll phin(ll n) {ll number = n; if (n % 2 == 0) {number /= 2; while (n % 2 == 0) n /= 2;} for (ll i = 3; i <= sqrt(n); i += 2) {if (n % i == 0) {while (n % i == 0)n /= i; number = (number / i * (i - 1));}} if (n > 1)number = (number / n * (n - 1)) ; return number;} //O(sqrt(N))



/*--------------------------------------------------------------------------------------------------------------------------*/

 

void solve() {

    int n;

    cin >> n;

    vector<int>a(n);

    for(int &i:a)cin>>i;

    if(n>1 && a[0]>=a[1]){

        cout<<"NO"<<endl;

        return;

    }

    

    for(int i=1;i<n;i++){ 

        if((a[i]-a[i-1])<=a[i+1]){

            a[i]=a[i]-a[i-1];

            continue;

        }

    }

    cout<<"YES"<<endl;



    

    

}



 

int main() {

#ifndef ONLINE_JUDGE

    freopen("Error.txt", "w", stderr);

#endif



     fastio();

    int t;

    cin>>t;

    while(t--)

      solve();

        

}



Submission (verdict: Wrong answer on test 10):
 /* Naman Gupta */

#include<bits/stdc++.h>

using namespace std;

 

#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)

#define MOD 1000000007

#define MOD1 998244353

#define INF 1e18

#define nline "\n"

#define pb push_back

#define ppb pop_back

#define mp make_pair

#define ff first

#define ss second

#define PI 3.141592653589793238462

#define set_bits __builtin_popcountll

#define sz(x) ((int)(x).size())

#define all(x) (x).begin(), (x).end()

 

#define ONLINE_JUDGE

#ifdef ONLINE_JUDGE

#define debug(x) cerr << #x<<" "; _print(x); cerr << endl;

#else

#define debug(x);

#endif

 

typedef long long ll;

typedef unsigned long long ull;

typedef long double lld;

typedef __int128 ell;

 

void _print(ll t) {cerr << t;}

void _print(int t) {cerr << t;}

void _print(string t) {cerr << t;}

void _print(char t) {cerr << t;}

void _print(lld t) {cerr << t;}

void _print(double t) {cerr << t;}

void _print(ull t) {cerr << t;}

 

template <class T, class V> void _print(pair <T, V> p);

template <class T> void _print(vector <T> v);

template <class T> void _print(set <T> v);

template <class T, class V> void _print(map <T, V> v);

template <class T> void _print(multiset <T> v);

template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}

template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

template <typename T> inline T Power(T a,T b){long long res=1;while(b>0){if(b&1){res=res*a;}a*=a;b>>=1;}return res;}

 

/*---------------------------------------------------------------------------------------------------------------------------*/

ll gcd(ll a, ll b) {if (b > a) {return gcd(b, a);} if (b == 0) {return a;} return gcd(b, a % b);}



ll expo(ll a, ll b, ll mod) {ll res = 1; while (b > 0) {if (b & 1)res = (res * a) % mod; a = (a * a) % mod; b = b >> 1;} return res;}

void extendgcd(ll a, ll b, ll*v) {if (b == 0) {v[0] = 1; v[1] = 0; v[2] = a; return ;} extendgcd(b, a % b, v); ll x = v[1]; v[1] = v[0] - v[1] * (a / b); v[0] = x; return;} //pass an arry of size1 3

ll mminv(ll a, ll b) {ll arr[3]; extendgcd(a, b, arr); return arr[0];} //for non prime b

ll mminvprime(ll a, ll b) {return expo(a, b - 2, b);}

bool revsort(ll a, ll b) {return a > b;}

ll combination(ll n, ll r, ll m, ll *fact, ll *ifact) {ll val1 = fact[n]; ll val2 = ifact[n - r]; ll val3 = ifact[r]; return (((val1 * val2) % m) * val3) % m;}

void google(int t) {cout << "Case #" << t << ": ";}

vector<ll> sieve(int n) {int*arr = new int[n + 1](); vector<ll> vect; for (int i = 2; i <= n; i++)if (arr[i] == 0) {vect.push_back(i); for (int j = 2 * i; j <= n; j += i)arr[j] = 1;} return vect;}

ll mod_add(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a + b) % m) + m) % m;}

ll mod_mul(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a * b) % m) + m) % m;}

ll mod_sub(ll a, ll b, ll m) {a = a % m; b = b % m; return (((a - b) % m) + m) % m;}

ll mod_div(ll a, ll b, ll m) {a = a % m; b = b % m; return (mod_mul(a, mminvprime(b, m), m) + m) % m;}  //only for prime m

ll phin(ll n) {ll number = n; if (n % 2 == 0) {number /= 2; while (n % 2 == 0) n /= 2;} for (ll i = 3; i <= sqrt(n); i += 2) {if (n % i == 0) {while (n % i == 0)n /= i; number = (number / i * (i - 1));}} if (n > 1)number = (number / n * (n - 1)) ; return number;} //O(sqrt(N))



/*--------------------------------------------------------------------------------------------------------------------------*/

 

void solve() {

    int n;

    cin >> n;

    vector<int>a(n);

    for(int &i:a)cin>>i;

    if(n>1 && a[0]>=a[1]){

        cout<<"NO"<<endl;

        return;

    }

    

    for(int i=1;i<n-1;i++){ 

        if((a[i]-a[i-1])<=a[i+1]){

            a[i]=a[i]-a[i-1];

            continue;

        }

        else if((a[i]-a[i-1])>a[i+1]){

             cout<<"NO"<<endl;

        return;

        }

    }

    cout<<"YES"<<endl;



    

    

}



 

int main() {

#ifndef ONLINE_JUDGE

    freopen("Error.txt", "w", stderr);

#endif



     fastio();

    int t;

    cin>>t;

    while(t--)

      solve();

        

}