Problem: 2060D - Subtract Min Sort
Language: java

Solution 1 (runtime: 655 ms):
import java.util.*;
import java.lang.*;
import java.math.BigInteger;
import java.io.*;
public class cf{
    // public static long gcd(long a,long b){
    //     while(a!=0 && b!=0){
    //         if(a<b){
    //             b=b%a;
    //         }else{
    //             a=a%b;
    //         }
    //     }
    //     if(a!=0){
    //         return a;
    //     }else{
    //         return b;
    //     }
    // }  
    // public static long lcm(long a,long b){
    //     return (a/gcd(a,b))*b;
    // }

    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        int tsts=sc.nextInt();
        for(int t=0;t<tsts;t++){
            int n=sc.nextInt();
            // int k=sc.nextInt();
            // int a4=sc.nextInt();
            // int a5=sc.nextInt();
            // int r2=sc.nextInt();
            // StringBuilder s=new StringBuilder(sc.next());
            // String a=sc.next();
            // String b=sc.next();
            // String c=sc.next();
            int[] a=new int[n];
            for(int i=0;i<n;i++){
                a[i]=sc.nextInt();
            }
            // int[] b=new int[n];
            // for(int i=0;i<n;i++){
            //     b[i]=sc.nextInt();
            // }
            // long n=sc.nextLong();
            // long k=sc.nextLong();
            // long r=sc.nextInt();
            // long c=sc.nextInt();
            for(int i=0;i<n-1;i++){
                int temp=Math.min(a[i],a[i+1]);
                a[i]-=temp;
                a[i+1]-=temp;
            }
            int[] b=new int[n];
            for(int i=0;i<n;i++){
                b[i]=a[i];
            }
            Arrays.sort(b);
            boolean flag=true;
            for(int i=0;i<n;i++){
                if(a[i]!=b[i]){
                    flag=false;
                    break;
                }
            }
            if(flag) System.out.println("Yes");
            else System.out.println("No");
        }    
    }
}

Solution 2 (runtime: 359 ms):
import java.io.*;

import java.math.*;

import java.util.*;



public class Main {

static class IoScanner {

BufferedReader bf;

StringTokenizer st;

BufferedWriter bw;



public IoScanner() {

bf = new BufferedReader(new InputStreamReader(System.in));

st = new StringTokenizer("");

bw = new BufferedWriter(new OutputStreamWriter(System.out));

}



public String nextLine() throws IOException {

return bf.readLine();

}



public String next() throws IOException {

while (!st.hasMoreTokens()) {

st = new StringTokenizer(bf.readLine());

}

return st.nextToken();

}



public char nextChar() throws IOException {

return next().charAt(0);

}



public int nextInt() throws IOException {

return Integer.parseInt(next());

}



public long nextLong() throws IOException {

return Long.parseLong(next());

}



public double nextDouble() throws IOException {

return Double.parseDouble(next());

}



public float nextFloat() throws IOException {

return Float.parseFloat(next());

}



public BigInteger nextBigInteger() throws IOException {

return new BigInteger(next());

}



public BigDecimal nextDecimal() throws IOException {

return new BigDecimal(next());

}

}

static IoScanner sc = new IoScanner();

static PrintWriter out = new PrintWriter(System.out);

static final int mod=(int) (1e9+7);

public static void main(String[] args) throws Exception {

int T = 1;

T = sc.nextInt();

while (T-- > 0) {

solve();

}

out.flush();

}

static void solve() throws IOException {

int n=sc.nextInt();

int[] arr = new int[n];

for(int i=0;i<n;i++){

arr[i]=sc.nextInt();

}

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

if (arr[i - 1] > arr[i]) {

out.println("NO");

return;

}else {

arr[i] -= arr[i - 1];

arr[i-1]=0;

}

}

out.println("YES");

}

}