n! means n × (n ? 1) × ... × 3 × 2 × 1
For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digi...
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其他好文 时间：
2015-05-31 15:22:58
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131
If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.
If all the numbers from 1 to 1000 (one thousand) inclusive we...
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其他好文 时间：
2015-05-31 12:33:14
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126
By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.
3
7 4
2 4 6
8 5 9 3
That is, 3 + 7 + 4 + 9 = 23.
Find th...
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其他好文 时间：
2015-05-31 12:30:05
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115
215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
What is the sum of the digits of the number 21000?
#include
#include
using namespace std;
int main()
{
string s = "1";
for (...
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其他好文 时间：
2015-05-31 11:01:20
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133
A Pythagorean triplet is a set of three natural numbers, a b c,
for which,
a2 + b2 = c2
For example, 32 + 42 = 9 + 16 = 25 = 52.
There exists exactly one Pythagorean triplet for which a + b + c...
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其他好文 时间：
2015-05-31 09:37:13
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172
The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:
1, 3, 6, 10, 15, 21, 28,...
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其他好文 时间：
2015-05-31 09:31:48
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165
The following iterative sequence is defined for the set of positive integers:
n → n/2 (n is
even)
n → 3n + 1 (n is
odd)
Using the rule above and starting with 13, we generate the following sequ...
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其他好文 时间：
2015-05-31 09:27:37
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117
Starting in the top left corner of a 2×2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.
How many such routes are there through a 20×...
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其他好文 时间：
2015-05-31 09:26:08
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135
Work out the first ten digits of the sum of the following one-hundred 50-digit numbers.
37107287533902102798797998220837590246510135740250
46376937677490009712648124896970078050417018260538
7432498...
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其他好文 时间：
2015-05-30 21:11:50
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130
In the 20×20 grid below, four numbers along a diagonal line have been marked in red.
08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56...
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其他好文 时间：
2015-05-30 18:17:36
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121
