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Time for an 2014 update…

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Ingy döt Net 2014-01-17 05:32:22 +00:00
parent 372c577f83
commit 09687c4926
2520 changed files with 34227 additions and 7318 deletions
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28
Task/Ackermann-function/D/ackermann-function-2.d
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@ -1,9 +1,8 @@
import std.stdio, std.bigint, std.conv;
/*pure nothrow*/ BigInt ipow(/*in*/ BigInt base, /*in*/ BigInt exp){
auto result = BigInt(1);
//while (exp) {
while (exp != 0) {
BigInt ipow(BigInt base, BigInt exp) pure /*nothrow*/ {
auto result = 1.BigInt;
while (exp) {
//if (exp & 1)
if (exp % 2)
result *= base;
@ -14,37 +13,36 @@ import std.stdio, std.bigint, std.conv;
return result;
}
/*pure nothrow*/ BigInt ackermann(in int m, in int n)
BigInt ackermann(in int m, in int n) pure /*nothrow*/
in {
assert(m >= 0 && n >= 0);
} out(result) {
//assert(result >= 0);
//assert(cast()result >= 0);
assert(result >= 0);
} body {
/*pure nothrow*/ static BigInt ack(in int m, /*in*/ BigInt n) {
static BigInt ack(in int m, in BigInt n) pure /*nothrow*/ {
switch (m) {
case 0: return n + 1;
case 1: return n + 2;
case 2: return 3 + 2 * n;
//case 3: return 5 + 8 * (2 ^^ n - 1);
case 3: return 5 + 8 * (ipow(BigInt(2), n) - 1);
case 3: return 5 + 8 * (ipow(2.BigInt, n) - 1);
default: if (n == 0)
return ack(m - 1, BigInt(1));
return ack(m - 1, 1.BigInt);
else
return ack(m - 1, ack(m, n - 1));
}
}
return ack(m, BigInt(n));
return ack(m, n.BigInt);
}
void main() {
foreach (m; 1 .. 4)
foreach (n; 1 .. 9)
foreach (immutable m; 1 .. 4)
foreach (immutable n; 1 .. 9)
writefln("ackermann(%d, %d): %s", m, n, ackermann(m, n));
writefln("ackermann(4, 1): %s", ackermann(4, 1));
auto a = text(ackermann(4, 2));
immutable a = ackermann(4, 2).text;
writefln("ackermann(4, 2)) (%d digits):\n%s...\n%s",
a.length, a[0 .. 94], a[$-96 .. $]);
a.length, a[0 .. 94], a[$ - 96 .. $]);
}