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stdlib: Make merge_sort take [mutable? T]

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This commit is contained in:
Brian Anderson 2011-10-28 13:56:01 -07:00
parent 39b729e36f
commit ad66d72e6c
2 changed files with 11 additions and 2 deletions
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5
src/lib/sort.rs
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@ -20,7 +20,7 @@ Merge sort. Returns a new vector containing the sorted list.
Has worst case O(n log n) performance, best case O(n), but Has worst case O(n log n) performance, best case O(n), but
is not space efficient. This is a stable sort. is not space efficient. This is a stable sort.
*/ */
fn merge_sort<T>(le: lteq<T>, v: [T]) -> [T] { fn merge_sort<T>(le: lteq<T>, v: [mutable? T]) -> [T] {
fn merge<T>(le: lteq<T>, a: [T], b: [T]) -> [T] { fn merge<T>(le: lteq<T>, a: [T], b: [T]) -> [T] {
let rs: [T] = []; let rs: [T] = [];
let a_len: uint = len::<T>(a); let a_len: uint = len::<T>(a);
@ -38,7 +38,8 @@ fn merge_sort<T>(le: lteq<T>, v: [T]) -> [T] {
ret rs; ret rs;
} }
let v_len: uint = len::<T>(v); let v_len: uint = len::<T>(v);
if v_len <= 1u { ret v; } if v_len == 0u { ret []; }
if v_len == 1u { ret [v[0]]; }
let mid: uint = v_len / 2u; let mid: uint = v_len / 2u;
let a: [T] = slice::<T>(v, 0u, mid); let a: [T] = slice::<T>(v, 0u, mid);
let b: [T] = slice::<T>(v, mid, v_len); let b: [T] = slice::<T>(v, mid, v_len);

8
src/test/stdtest/sort.rs
View File

@ -26,3 +26,11 @@ fn test() {
check_sort(v1, v2); check_sort(v1, v2);
} }
} }
#[test]
fn test_merge_sort_mutable() {
fn lteq(&&a: int, &&b: int) -> bool { ret a <= b; }
let v1 = [mutable 3, 2, 1];
let v2 = std::sort::merge_sort(lteq, v1);
assert v2 == [1, 2, 3];
}