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use std;
import std.Int;
tag tree {
nil;
node(@tree, @tree, int);
}
fn item_check(@tree t) -> int {
alt (*t) {
case (nil) {
ret 0;
}
case (node(?left, ?right, ?item)) {
ret item + item_check(left) - item_check(right);
}
}
}
fn bottom_up_tree(int item, int depth) -> @tree{
if (depth > 0) {
ret @node(bottom_up_tree(2 * item - 1, depth - 1),
bottom_up_tree(2 * item, depth - 1),
item);
} else {
ret @nil;
}
}
fn main() {
auto n = 8;
auto min_depth = 4;
auto max_depth;
if (min_depth + 2 > n) {
max_depth = min_depth + 2;
} else {
max_depth = n;
}
auto stretch_depth = max_depth + 1;
auto stretch_tree = bottom_up_tree(0, stretch_depth);
log #fmt("stretch tree of depth %d\t check: %d",
stretch_depth, item_check(stretch_tree));
auto long_lived_tree = bottom_up_tree(0, max_depth);
auto depth = min_depth;
while (depth <= max_depth) {
auto iterations = Int.pow(2, (max_depth - depth + min_depth) as uint);
auto chk = 0;
auto i = 1;
while (i <= iterations) {
auto temp_tree = bottom_up_tree(i, depth);
chk += item_check(temp_tree);
temp_tree = bottom_up_tree(-i, depth);
chk += item_check(temp_tree);
i += 1;
}
log #fmt("%d\t trees of depth %d\t check: %d",
iterations * 2, depth, chk);
depth += 2;
}
log #fmt("long lived trees of depth %d\t check: %d",
max_depth, item_check(long_lived_tree));
}
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