Problem: 2060D - Subtract Min Sort
Language: java

Solution 1 (runtime: 702 ms):
import java.util.*;
         
public class CompCode {
    static Scanner sc = new Scanner(System.in);
 
    static int MOD = 998244353; 
 
    public static void main(String... args) {
        int tc = sc.nextInt();
        while(tc-- > 0) {
            int n = sc.nextInt();
            int[] a = new int[n];
            int i;
            for(i=0; i<n; i++) {
                a[i] = sc.nextInt();
            }

            if(n==2) {
                if(a[1]>=a[0]) {
                    System.out.println("YES");
                } else {
                    System.out.println("NO");
                }
                continue;
            }

            for(i=1; i<n-1; i++) {
                if(a[i]<a[i-1]) {
                    break;
                }
                if(a[i]-a[i-1] > a[i+1]) {
                    break;
                }
                a[i] = a[i]-a[i-1];
                // System.out.print(a[i]+ " ");
            }
            if(i==n-1) {
                System.out.println("YES");
            } else {
                System.out.println("NO");
            }
        } 
    }
}

Solution 2 (runtime: 312 ms):
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class prob {

    static class FastReader {
        BufferedReader b;
        StringTokenizer s;

        public FastReader() {
            b = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (s == null || !s.hasMoreElements()) {
                try {
                    s = new StringTokenizer(b.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return s.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        float nextFloat() {
            return Float.parseFloat(next());
        }

        boolean nextBoolean() {
            return Boolean.parseBoolean(next());
        }

        // Method to read the next line as a string
        String nextLine() {
            String str = "";
            try {
                if (s == null || !s.hasMoreTokens()) {
                    str = b.readLine();
                } else {
                    str = s.nextToken("\n");
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }

    //===================================================================================================

    public static void main(String[] args) {
        FastReader fastReader = new FastReader();

        int t=0;
        t = fastReader.nextInt();

        while(t-- >0){
            int n = fastReader.nextInt();
            int[] arr = new int[n];

            for(int i=0;i<n;i++){
                arr[i] = fastReader.nextInt();
            }

            solve(arr, n);
        }
    }

    public static void solve(int[] arr, int n){

        for(int i=0;i<n-1;i++){
            int var = Math.min(arr[i], arr[i+1]);
            arr[i]-=var;
            arr[i+1]-=var;
        }

        for(int i=0;i<n-1;i++){
            if(arr[i+1]<arr[i]){
                System.out.println("NO");
                return;
            }
        }

        System.out.println("YES");
    }
}