901 B | 901 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
# sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
n = ii()
l = mii()
crt = l[n - 1]
alter = n - crt + 1
if crt < alter:
l[n - 1] = alter
for i in range(n - 2, -1, - 1):
crt = l[i]
alter = n - crt + 1
if (crt < alter or crt > l[i + 1])and alter <= l[i + 1]:
l[i] = alter
for i in range(n - 1):
if l[i] > l[i + 1]:
p("NO")
return
p("YES")
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()