package main

import (
	"fmt"
)

func main() {
	var t int
	if _, err := fmt.Scan(&t); err != nil {
		return
	}
	for i := 0; i < t; i++ {
		var n int
		fmt.Scan(&n)
		x := make([]int, n)
		for j := 0; j < n; j++ {
			fmt.Scan(&x[j])
		}
		if n == 2 && x[1]-x[0] > 1 {
			fmt.Println("YES")
		} else {
			fmt.Println("NO")
		}
	}
}