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Just another update

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Ingy döt Net 2015-02-20 00:35:01 -05:00
parent a25938f123
commit 00a190b0a6
6591 changed files with 94363 additions and 23227 deletions
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17
Task/Ackermann-function/D/ackermann-function-2.d
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@ -1,6 +1,6 @@
import std.stdio, std.bigint, std.conv;
BigInt ipow(BigInt base, BigInt exp) pure /*nothrow*/ {
BigInt ipow(BigInt base, BigInt exp) pure nothrow {
auto result = 1.BigInt;
while (exp) {
if (exp & 1)
@ -12,23 +12,20 @@ BigInt ipow(BigInt base, BigInt exp) pure /*nothrow*/ {
return result;
}
BigInt ackermann(in int m, in int n) pure /*nothrow*/
in {
assert(m >= 0 && n >= 0);
} out(result) {
BigInt ackermann(in uint m, in uint n) pure nothrow
out(result) {
assert(result >= 0);
} body {
static BigInt ack(in int m, in BigInt n) pure /*nothrow*/ {
static BigInt ack(in uint 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(2.BigInt, n) - 1);
default: if (n == 0)
return ack(m - 1, 1.BigInt);
else
return ack(m - 1, ack(m, n - 1));
default: return (n == 0) ?
ack(m - 1, 1.BigInt) :
ack(m - 1, ack(m, n - 1));
}
}