RAINBOWB codechef Sept 14

Could anybody explain all the testcases without giving any hints?

for N=10, No Possible Rainbow Array

for N=13 , 1234567654321

for N=14, 12345677654321

for N=15, 112345676543211
122345676543221
123345676543321
123445676544321
123455676554321
123456676654321
123456777654321

Hope it Helps.

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