Problem: 2060D - Subtract Min Sort
Language: java

Solution 1 (runtime: 218 ms):
import java.util.*;

import java.io.*;
	
			public class Main {
				

 
			public static void main(String[] args) throws FileNotFoundException,IOException, InterruptedException {
				Scanner s=new Scanner(System.in);
				PrintWriter pw=new PrintWriter(System.out);	
				
				
				int t=s.nextInt();
				while (t-->0)
				{
					int n=s.nextInt();
					int[]a=s.nextIntArr(n);
					boolean ans = true;
					for (int i=0; i<n-1;i++)
					{
						if (a[i] > a[i+1])
						{
							ans=false;
							break;
						}
						else {
							a[i+1]-=a[i];
							a[i]=0;
						}
					}
					for (int i=1; i<n;i++)
						ans&=a[i]>=a[i-1];
					pw.println(ans?"YES":"NO");
					
				}	
				pw.flush();
				
			}
			
			
			// used with hashmap or treemap
			// value should be integer, element type matches key
			static void putOrIncreaseCounter(int element, TreeMap<Integer, Integer> tm)
			{
				if (tm.containsKey(element))
					tm.put(element, tm.get(element)+1);
				else tm.put(element, 1);
			}
			
			
			// used with hashmap or treemap
			// value should be integer, element type matches key
			static void removeOrDecreaseCounter(int element, TreeMap<Integer, Integer> tm)
			{
				if (!tm.containsKey(element))
					return;
				if (tm.get(element)>1)
					tm.put(element, tm.get(element)-1);
				else tm.remove(element);
			}
			
	
			
			 static void shuffle(int []a)
			{	
				for (int i=0; i<a.length;i++)
				{
					int randIndex=(int)(Math.random()*a.length);
					int temp=a[i];
					a[i]=a[randIndex];
					a[randIndex]=temp;
				}
				
			}
			
			 static int gcd(int a, int b) // O(log(min(a,b))
		    {
			      if (b == 0)
			        return a;
			      return gcd(b, a % b); 
			    }
			
			static class Scanner 
			{
				StringTokenizer st;
				BufferedReader br;
		
				public Scanner() {
				br = new BufferedReader(new InputStreamReader(System.in));
				}		
				public Scanner(String s) throws FileNotFoundException
				{
					br =new BufferedReader(new FileReader(s));
				}
		
				public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}
		
		
				public String next() throws IOException 
				{
					while (st == null || !st.hasMoreTokens()) 
						st = new StringTokenizer(br.readLine());
					return st.nextToken();
				}
		
				public int nextInt() throws IOException {return Integer.parseInt(next());}
				
				public long nextLong() throws IOException {return Long.parseLong(next());}
		
				public String nextLine() throws IOException {return br.readLine();}
				
				public double nextDouble() throws IOException
				{
					String x = next();
					StringBuilder sb = new StringBuilder("0");
					double res = 0, f = 1;
					boolean dec = false, neg = false;
					int start = 0;
					if(x.charAt(0) == '-')
					{
						neg = true;
						start++;
					}
					for(int i = start; i < x.length(); i++)
						if(x.charAt(i) == '.')
						{
							res = Long.parseLong(sb.toString());
							sb = new StringBuilder("0");
							dec = true;
						}
						else
						{
							sb.append(x.charAt(i));
							if(dec)
								f *= 10;
						}
					res += Long.parseLong(sb.toString()) / f;
					return res * (neg?-1:1);
				}
				 public long[] nextLongArr(int n) throws IOException {
			            long[] arr = new long[n];
			            for (int i = 0; i < n; i++)
			                arr[i] = nextLong();
			            return arr;
			        }
		
			        public int[] nextIntArr(int n) throws IOException {
			            int[] arr = new int[n];
			            for (int i = 0; i < n; i++)
			                arr[i] = nextInt();
			            return arr;
			        }
				
				public boolean ready() throws IOException {return br.ready();}
				
				 
			} //end scanner
			
			
			
		
			
	}
		
	
		 class Pair implements Comparable{
			int x;
			int y;
			Pair(int x, int y)
			{
				this.x=x;
				this.y=y;
			}
			@Override
//			public int compareTo(Object o) {
//				Pair p=(Pair)o;
//				 return  this.x-p.x;
//			}
			public int compareTo(Object o)
			{
				Pair p=(Pair)o;
				return this.x==p.x?this.y-p.y:this.x-p.x;
			}
			public String toString()
			{
				return "("+x+","+y+")";
			}
			
		}
		
		 
		 class Edge implements Comparable<Edge> {
				int node, cost; //node to go to 
			
				Edge(int a, int b) {
					node = a;
					cost = b;
				}
			
				public int compareTo(Edge e) {
					return cost - e.cost;
				}
				public String toString()
				{
					return "{ "+this.node+","+this.cost+" }";
				}
		 
		 	 
		 } 
		 
		 
		

Solution 2 (runtime: 343 ms):
import java.io.*;
import java.util.*;
import static java.lang.Math.*;
public class  MyCPTemplate{
    static final int MOD = (int) (1e9 + 7);static final int INF = (int) (1e9) + 10;


    // safe use long
    static void solve() throws IOException{
        int n = fr.nextInt();
        int[] a = new int[n];

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


        int i = 0;

        while(i<n-1){
            if(a[i]>a[i+1]){
                out.println("no");
                return;
            }

            else if(a[i]<a[i+1]){
                a[i+1]-=a[i];
                i++;
            }
            else{
                i+=2;
            }
        }

        out.println("yes");
    }


    public static void main(String[] args) throws Exception {
        int t = 1;
        t = fr.nextInt();
        while (t-->0){
            solve();
        }

        out.close();
    }


    //------------------------------------------------------------------------------------------------------------------//
    static void debug(Object... argObjects) throws IOException {out.println(Arrays.deepToString(argObjects));}
    static FastReader fr = new FastReader();
    static FastWriter out = new FastWriter();
    static class Pair<F extends Comparable<F>,S extends Comparable<S>> implements Comparable<Pair<F,S>>{
        public F first;
        public S second;
        public Pair(){}
        public Pair(F k,S v){
            first = k;
            second = v;
        }
        public String toString(){
            return "(" + first + ", " + second + ")";
        }

        @Override
        public int compareTo(Pair<F, S> that) {
            int cmp = this.first.compareTo(that.first);
            if (cmp == 0) {
                return this.second.compareTo(that.second);
            }
            return cmp;
        }
    }
    static class FastReader {

        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in),1<<18);
        }

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

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

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

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

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
    static class FastWriter {
        private final BufferedWriter bw;

        public FastWriter() {
            bw = new BufferedWriter(new OutputStreamWriter(System.out), 1 << 18);
        }

        // Print a single value
        public void print(String s) throws IOException {
            bw.write(s);
        }

        public void print(int x) throws IOException {
            bw.write(Integer.toString(x));
        }

        public void print(long x) throws IOException {
            bw.write(Long.toString(x));
        }

        public void print(double x) throws IOException {
            bw.write(Double.toString(x));
        }
        public void print(Object obj) throws IOException{
            bw.write(obj.toString());
        }

        // Print a value with a newline
        public void println(String s) throws IOException {
            bw.write(s);
            bw.newLine();
        }
        public void println() throws IOException {
            bw.newLine();
        }

        public void println(int x) throws IOException {
            bw.write(Integer.toString(x));
            bw.newLine();
        }

        public void println(long x) throws IOException {
            bw.write(Long.toString(x));
            bw.newLine();
        }

        public void println(double x) throws IOException {
            bw.write(Double.toString(x));
            bw.newLine();
        }
        public void println(Object obj) throws IOException {
            bw.write(obj.toString());
            bw.newLine();
        }



        // Print arrays
        public void printArray(int[] arr) throws IOException {
            for (int x : arr) {
                print(x + " ");
            }
            println("");
        }

        public void printArray(int[][] arr) throws IOException{
            for(int[] a: arr){
                for(int i:a){
                    print(i+" ");
                }
                println();
            }
        }


        public void printArray(long[] arr) throws IOException {
            for (long x : arr) {
                print(x + " ");
            }
            println("");
        }

        // Print collections
        public <T> void printCollection(Collection<T> col) throws IOException {
            for (T x : col) {
                print(x.toString() + " ");
            }
            println("");
        }

        // Flush the buffer
        public void flush() throws IOException {
            bw.flush();
        }

        // Close the writer
        public void close() throws IOException {
            bw.close();
        }
    }



    /*
         Random stuff to try when stuck:
            -if it's 2C then it's dp
            -for combo/probability problems, expand the given form we're interested in
            -make everything the same then build an answer (constructive, make everything 0 then do something)
            -something appears in parts of 2 --> model as graph
            -assume a greedy then try to show why it works
            -find way to simplify into one variable if multiple exist
            -treat it like fmc (note any passing thoughts/algo that could be used so you can revisit them)
            -find lower and upper bounds on answer
            -figure out what ur trying to find and isolate it
            -see what observations you have and come up with more continuations
            -work backwards (in constructive, go from the goal to the start)
            -turn into prefix/suffix sum argument (often works if problem revolves around adjacent array elements)
            -instead of solving for answer, try solving for complement (ex, find n-(min) instead of max)
            -draw something
            -simulate a process
            -dont implement something unless if ur fairly confident its correct
            -after 3 bad submissions move on to next problem if applicable
            -do something instead of nothing and stay organized
            -write stuff down
            -check for some values which might be incorrect --> ((long)sqrt(n) does not always give the max number t*t<=n, adjust t).
         Random stuff to check when wa:
            -if code is way too long/cancer then reassess
            -switched N/M
            -int overflow
            -switched variables
            -wrong MOD
            -hardcoded edge case incorrectly
         Random stuff to check when tle:
            -continue instead of break
            -condition in for/while loop bad
         Random stuff to check when rte:
            -switched N/M
            -long to int/int overflow
            -division by 0
            -edge case for empty list/data structure/N=1
      */
}