From 7fd4212ad2fd90a5cfad02b9f33ee2e769960b36 Mon Sep 17 00:00:00 2001
From: frederik stehli <frederik.stehli@udo.edu>
Date: Fri, 6 Jul 2018 08:27:39 +0200
Subject: [PATCH] [min_max] worked on bwd search
---
src/datastructures/min_max.rs | 73 ++++++++++++++++++++++++++++++++++-
1 file changed, 72 insertions(+), 1 deletion(-)
diff --git a/src/datastructures/min_max.rs b/src/datastructures/min_max.rs
index 1ca06a8..8b90b01 100644
--- a/src/datastructures/min_max.rs
+++ b/src/datastructures/min_max.rs
@@ -278,7 +278,69 @@ impl MinMax {
}
fn bwd_search(&self, index: u64, diff: i64) -> Result<u64, NodeError> {
- unimplemented!();
+
+ let mut block_no= index / self.block_size;
+ let mut begin_of_block = block_no * self.block_size;
+ let mut end_of_block = begin_of_block + self.block_size - 1;
+ let mut current_node = (self.heap.len() / 2) as u64 + block_no;
+
+ let index_excess = self.excess(index).unwrap() as i64;
+ let mut current_excess = index_excess as i64;
+
+ let mut position = index;
+ let mut found = false;
+
+ while !found && position > begin_of_block {
+ if self.bits[position]{
+ current_excess -= 1;
+ } else {
+ current_excess += 1;
+ }
+ position -= 1;
+ if current_excess == index_excess + diff {
+ found = true;
+ }
+ }
+
+ if !found {
+ let mut look_for = diff + index_excess - current_excess;
+ let mut bottom_up = true;
+ let mut top_down = false;
+
+ while bottom_up && current_node > 0 {
+ if current_node % 2 == 0 {
+ if self.heap[current_node as usize -1].max_excess >= look_for &&
+ self.heap[current_node as usize -1].min_excess <= look_for {
+ bottom_up = false;
+ top_down = true;
+ current_node -= 1;
+ } else {
+ look_for = look_for + self.heap[current_node as usize -1].excess;
+ current_node = (current_node - 1) / 2;
+ }
+ } else {
+ current_node = (current_node - 1) / 2;
+ }
+ }
+
+ while top_down {
+ if self.heap[current_node as usize * 2 + 2].max_excess >= look_for &&
+ self.heap[current_node as usize * 2 + 2].min_excess <= look_for {
+ current_node = current_node * 2 + 2;
+ } else if self.heap[current_node as usize * 2 + 1].max_excess >= look_for &&
+ self.heap[current_node as usize * 2 + 1].min_excess <= look_for {
+ current_node = current_node * 2 + 1;
+
+ }
+
+ if current_node < self.heap.len() as u64 / 2 {
+ top_down = false;
+ }
+ }
+
+ }
+
+ Ok(1)
}
pub fn find_close(&self, index: u64) -> Result<u64, NodeError> {
@@ -404,6 +466,15 @@ mod tests {
assert_eq!(min_max.find_close(1).unwrap(), 2);
}
+ #[test]
+ #[ignore]
+ fn test_bwd_search() {
+ let bits =
+ bit_vec![true, true, true, false, true, false, false, true, true, false, false, false];
+ let min_max = MinMax::new(bits, 4);
+ assert_eq!(min_max.bwd_search(0, 0).unwrap(), 11);
+ }
+
#[test]
#[ignore]
fn test_enclose() {
--
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