Canon/open_set/80_k_smallest.pas

85 lines
1.2 KiB
ObjectPascal

program FindSmallest;
const
space = 32;
var
arr: array[0..999] of integer;
n, k, i, low, high: integer;
procedure swap(a, b: integer);
var
tmp: integer;
begin
tmp := arr[a];
arr[a] := arr[b];
arr[b] := tmp;
end;
function findPivot(start, endIndex: integer): integer;
var
pivot, pIndex, i: integer;
begin
pivot := arr[endIndex];
pIndex := start;
for i := start to endIndex - 1 do
begin
if arr[i] <= pivot then
begin
swap(i, pIndex);
pIndex := pIndex + 1;
end;
end;
swap(pIndex, endIndex);
findPivot := pIndex;
end;
procedure findSmallest(low, high, k, n: integer);
var
pIndex, i: integer;
begin
if low <> high then
begin
pIndex := findPivot(low, high);
if k = pIndex then
begin
for i := 0 to pIndex - 1 do
begin
write(arr[i]);
end;
end
else if k < pIndex then
begin
findSmallest(low, pIndex - 1, k, n);
end
else
begin
findSmallest(pIndex + 1, high, k, n);
end;
end;
end;
function getint: integer;
var
n: integer;
begin
read(n);
getint := n;
end;
begin
n := getint;
k := getint;
for i := 0 to n - 1 do
begin
arr[i] := getint;
end;
low := 0;
high := n - 1;
findSmallest(low, high, k, n);
end.