Test System

Most of my development is done on a Intel® Core™ i7-2600K CPU @ 3.40GHz.
My default compiler is G++ with a x86_64 target and its command-line settings are
g++ -O3 -march=native -fno-exceptions -fno-rtti -std=c++11

Execution Time

The majority of my C++ solutions need much longer to compile than to run.
The "slowest" solutions are (user time displayed by time):

problem seconds
211 - Divisor Square Sum 14.64 seconds
229 - Four Representations using Squares 10.46 seconds
103 - Special subset sums: optimum 4.27 seconds
146 - Investigating a Prime Pattern 3.21 seconds
214 - Totient Chains 2.69 seconds
  60 - Prime pair sets 1.69 seconds
  70 - Totient permutation 1.51 seconds
136 - Singleton differences 1.21 seconds
145 - How many reversible numbers are there below one ... 0.80 seconds
179 - Consecutive positive divisors 0.78 seconds
Note: 120 out of 160 solutions find the correct result in less than 0.1 seconds.

Memory Consumption

The GCC standard library consumes about 2 MByte RAM (basic I/O, etc.).

problem peak RAM consumption
165 - Intersections 68.9 MB
193 - Squarefree Numbers 39.1 MB
  75 - Singular integer right triangles 26.3 MB
179 - Consecutive positive divisors 21.6 MB
  39 - Integer right triangles 21.3 MB
  87 - Prime power triples 20.1 MB
113 - Non-bouncy numbers 18.4 MB
211 - Divisor Square Sum 17.9 MB
149 - Searching for a maximum-sum subsequence 17.6 MB
187 - Semiprimes 16.5 MB
Note: 120 out of 160 solutions allocate less than 2.5 MByte.

Some solutions could be modified to use smaller data types, especially because an int is 8 bytes on my system (64 bit compiler).

Code Metrics

C++ programs tend to be a bit longer than other popular languages (such as Python).
The metric "lines of code" excludes comments, empty lines and preprocessor commands.

problem lines of code comments blank lines
  80 - Square root digital expansion 234 66 42
  60 - Prime pair sets 204 65 38
  54 - Poker hands 188 28 26
146 - Investigating a Prime Pattern 187 59 41
  98 - Anagramic squares 169 49 42
  50 - Consecutive prime sum 168 46 38
119 - Digit power sum 159 34 27
  90 - Cube digit pairs 141 32 28
  66 - Diophantine equation 136 30 25
  33 - Digit cancelling fractions 123 40 19
Note: 81 out of 160 solutions have less than 50 lines of code.

Heatmap

green problems solve the original Project Euler problem and have a perfect score of 100% at Hackerrank, too.
yellow problems score less than 100% at Hackerrank (but still solve the original problem).
gray problems are already solved but I haven't published my solution yet.
blue problems are solved and there wasn't a Hackerrank version of it at the time I solved it or I didn't care about it because it differed too much.

Please click on a problem's number to open my solution to that problem:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175
176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200
201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250
The 160 solved problems had an average difficulty of 21.8% at Project Euler and I scored 11,807 points (out of 13100) at Hackerrank's Project Euler+.
My username at Project Euler is stephanbrumme while it's stbrumme at Hackerrank.
more about me can be found on my homepage.
some names mentioned on this site may be trademarks of their respective owners.
thanks to the KaTeX team for their great typesetting library !