3+33+333+.+333...333（1000个）
= ( 9 + 99 + 999 + ...+ 999...999(1000个) ) / 3
= (10-1 + 100-1 + 1000-1 + ...+ 1000...000(1000个0)-1 ) /3
= (111...11110(1000个1) - 1000 ) /3
= 111...1110110 / 3
999个1
= 370370...370(332个370)3370 ---- 3370 = 10110 / 3
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