Knuth's algorithm S: Difference between revisions
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m (→{{header|Phix}}: added syntax colouring, marked p2js compatible) |
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of course an s_of_n() that operated directly on local vars rather than elements of env, would be faster still.<br> |
of course an s_of_n() that operated directly on local vars rather than elements of env, would be faster still.<br> |
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Not that a mere 100,000 samples takes any method more than a tiny fraction of a second, you understand. |
Not that a mere 100,000 samples takes any method more than a tiny fraction of a second, you understand. |
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<lang Phix> |
<!--<lang Phix>(phixonline)--> |
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<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span> |
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<span style="color: #008080;">enum</span> <span style="color: #000000;">RID</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">I</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">SAMPLE</span> |
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function s_of_n(sequence env, integer item) |
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integer i = env[I] + 1, |
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<span style="color: #008080;">function</span> <span style="color: #000000;">s_of_n</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">env</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">item</span><span style="color: #0000FF;">)</span> |
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n = length(env[SAMPLE]) |
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<span style="color: #004080;">integer</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">I</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> |
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env[I] = i |
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<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">])</span> |
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if i<=n then |
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<span style="color: #000000;">env</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">deep_copy</span><span style="color: #0000FF;">(</span><span style="color: #000000;">env</span><span style="color: #0000FF;">)</span> |
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env[SAMPLE][i] = item |
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<span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">I</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">i</span> |
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elsif n/i>rnd() then |
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<span style="color: #008080;">if</span> <span style="color: #000000;">i</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">n</span> <span style="color: #008080;">then</span> |
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env[SAMPLE][rand(n)] = item |
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<span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">][</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">item</span> |
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end if |
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<span style="color: #008080;">elsif</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">/</span><span style="color: #000000;">i</span><span style="color: #0000FF;">></span><span style="color: #7060A8;">rnd</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">then</span> |
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return env |
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<span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">][</span><span style="color: #7060A8;">rand</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">item</span> |
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end function |
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<span style="color: #008080;">end</span> <span style="color: #008080;">if</span> |
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<span style="color: #008080;">return</span> <span style="color: #000000;">env</span> |
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function s_of_n_creator(int n) |
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<span style="color: #008080;">end</span> <span style="color: #008080;">function</span> |
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return {routine_id("s_of_n"),0,repeat(0,n)} |
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end function |
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<span style="color: #008080;">function</span> <span style="color: #000000;">s_of_n_creator</span><span style="color: #0000FF;">(</span><span style="color: #004080;">int</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> |
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<span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">s_of_n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)}</span> |
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function invoke(sequence env, args) |
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<span style="color: #008080;">end</span> <span style="color: #008080;">function</span> |
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env = call_func(env[RID],prepend(args,env)) |
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return env |
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<span style="color: #008080;">function</span> <span style="color: #000000;">invoke</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">env</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">args</span><span style="color: #0000FF;">)</span> |
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end function |
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<span style="color: #000000;">env</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">call_func</span><span style="color: #0000FF;">(</span><span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">RID</span><span style="color: #0000FF;">],</span><span style="color: #7060A8;">prepend</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">deep_copy</span><span style="color: #0000FF;">(</span><span style="color: #000000;">args</span><span style="color: #0000FF;">),</span><span style="color: #000000;">env</span><span style="color: #0000FF;">))</span> |
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<span style="color: #008080;">return</span> <span style="color: #000000;">env</span> |
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function test(integer n, sequence items) |
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<span style="color: #008080;">end</span> <span style="color: #008080;">function</span> |
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sequence env = s_of_n_creator(n) |
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for i=1 to length(items) do |
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<span style="color: #008080;">function</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">items</span><span style="color: #0000FF;">)</span> |
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-- env = s_of_n(env,items[i]) |
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<span style="color: #004080;">sequence</span> <span style="color: #000000;">env</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s_of_n_creator</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> |
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env = invoke(env, {items[i]}) |
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<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">items</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> |
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end for |
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<span style="color: #000080;font-style:italic;">-- env = s_of_n(env,items[i])</span> |
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return env[SAMPLE] |
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<span style="color: #000000;">env</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">invoke</span><span style="color: #0000FF;">(</span><span style="color: #000000;">env</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">items</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]})</span> |
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end function |
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<span style="color: #008080;">end</span> <span style="color: #008080;">for</span> |
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<span style="color: #008080;">return</span> <span style="color: #000000;">env</span><span style="color: #0000FF;">[</span><span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">]</span> |
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procedure main() |
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<span style="color: #008080;">end</span> <span style="color: #008080;">function</span> |
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sequence items_set = tagset(9,0) |
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sequence frequencies = repeat(0,length(items_set)) |
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<span style="color: #008080;">procedure</span> <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span> |
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for i=1 to 100000 do |
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<span style="color: #004080;">sequence</span> <span style="color: #000000;">items_set</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">9</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span> |
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sequence res = test(3, items_set) |
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<span style="color: #004080;">sequence</span> <span style="color: #000000;">frequencies</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">items_set</span><span style="color: #0000FF;">))</span> |
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for j=1 to length(res) do |
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<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">100000</span> <span style="color: #008080;">do</span> |
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frequencies[res[j]+1] += 1 |
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<span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">items_set</span><span style="color: #0000FF;">)</span> |
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end for |
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<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> |
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end for |
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<span style="color: #004080;">integer</span> <span style="color: #000000;">fdx</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">res</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">]+</span><span style="color: #000000;">1</span> |
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?frequencies |
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<span style="color: #000000;">frequencies</span><span style="color: #0000FF;">[</span><span style="color: #000000;">fdx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span> |
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end procedure |
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<span style="color: #008080;">end</span> <span style="color: #008080;">for</span> |
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main()</lang> |
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<span style="color: #008080;">end</span> <span style="color: #008080;">for</span> |
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<span style="color: #0000FF;">?</span><span style="color: #000000;">frequencies</span> |
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<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span> |
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<span style="color: #000000;">main</span><span style="color: #0000FF;">()</span> |
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<!--</lang>--> |
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{{out}} |
{{out}} |
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<pre> |
<pre> |
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</pre> |
</pre> |
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Note that s_of_n_creator() must match {RID, I, SAMPLE}. You might instead prefer (taking the appropriate care not to miss any!): |
Note that s_of_n_creator() must match {RID, I, SAMPLE}. You might instead prefer (taking the appropriate care not to miss any!): |
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<lang Phix> |
<!--<lang Phix>(phixonline)--> |
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<span style="color: #008080;">enum</span> <span style="color: #000000;">RID</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">I</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">CLOSURE_LEN</span><span style="color: #0000FF;">=$</span> |
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... |
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<span style="color: #0000FF;">...</span> |
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function s_of_n_creator(int n) |
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<span style="color: #008080;">function</span> <span style="color: #000000;">s_of_n_creator</span><span style="color: #0000FF;">(</span><span style="color: #004080;">int</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> |
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sequence closure = repeat(0,CLOSURE_LEN) |
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<span style="color: #004080;">sequence</span> <span style="color: #000000;">closure</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">CLOSURE_LEN</span><span style="color: #0000FF;">)</span> |
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closure[RID] = routine_id("s_of_n") |
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<span style="color: #000000;">closure</span><span style="color: #0000FF;">[</span><span style="color: #000000;">RID</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">routine_id</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"s_of_n"</span><span style="color: #0000FF;">)</span> |
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closure[I] = 0 |
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<span style="color: #000000;">closure</span><span style="color: #0000FF;">[</span><span style="color: #000000;">I</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span> |
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closure[SAMPLE] = repeat(0,n) |
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<span style="color: #000000;">closure</span><span style="color: #0000FF;">[</span><span style="color: #000000;">SAMPLE</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> |
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return closure |
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<span style="color: #008080;">return</span> <span style="color: #000000;">closure</span> |
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end function</lang> |
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<span style="color: #008080;">end</span> <span style="color: #008080;">function</span> |
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<!--</lang>--> |
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=={{header|PHP}}== |
=={{header|PHP}}== |