Can anyone plz help me with this problem?Problem
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Just precalculate all factorials in the range [0, 107] modulo 1000000000000037.
Then the rest is just range sum.
Edit. I tried it out. The answer is correct. But I didn't notice the memory limit (This solution will get MLE). Sorry.
Lets solve it offline. There are maximum 2*n different numbers. Calculate factorial only for this numbers. Notice that, when we multiplying the big numbers, there can exists number that > 1023. So use binary multiplying.
You can use 1000-ary multiplication as given (mod = 10 ^15) * 10 ^ 3 < MAX_LONG_INT. It will cost maximum of only 3 operations reducing the log(n) factor.