814de27a42
Co-authored-by: zzg19950727 <1071026277@qq.com> Co-authored-by: xianyu-w <707512433@qq.com>
104 lines
2.6 KiB
C++
104 lines
2.6 KiB
C++
// Copyright (c) 2015 Alibaba Inc. All Rights Reserved.
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// Author:
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// zhenling.zzg
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#define USING_LOG_PREFIX SQL_REWRITE
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#include "sql/rewrite/ob_union_find.h"
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namespace oceanbase
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{
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using namespace common;
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namespace sql
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{
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int UnionFind::init()
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{
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int ret = OB_SUCCESS;
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if (OB_UNLIKELY(is_inited_)) {
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ret = OB_INIT_TWICE;
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LOG_WARN("init twice", K(ret));
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} else {
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for (int64_t i = 0; OB_SUCC(ret) && i < count_; ++i) {
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if (OB_FAIL(parent_.push_back(i))) {
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LOG_WARN("failed to push back node", K(ret));
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} else if (OB_FAIL(tree_size_.push_back(1))) {
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LOG_WARN("failed to push back size", K(ret));
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}
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}
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if (OB_SUCC(ret)) {
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is_inited_ = true;
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}
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}
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return ret;
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}
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int UnionFind::connect(int64_t p, int64_t q)
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{
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int ret = OB_SUCCESS;
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int64_t root_p = OB_INVALID_INDEX;
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int64_t root_q = OB_INVALID_INDEX;
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if (OB_UNLIKELY(!is_inited_)) {
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ret = OB_NOT_INIT;
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LOG_WARN("union find is not initialized", K(ret));
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} else if (OB_FAIL(find_root(p, root_p))) {
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LOG_WARN("failed to find node", K(ret));
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} else if (OB_FAIL(find_root(q, root_q))) {
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LOG_WARN("failed to find node", K(ret));
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} else if (root_p != root_q) {
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if (tree_size_.at(root_p) > tree_size_.at(root_q)) {
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parent_.at(root_q) = root_p;
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tree_size_.at(root_p) += tree_size_.at(root_q);
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} else {
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parent_.at(root_p) = root_q;
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tree_size_.at(root_q) += tree_size_.at(root_p);
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}
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--count_;
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}
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return ret;
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}
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int UnionFind::find_root(int64_t x, int64_t &root)
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{
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int ret = OB_SUCCESS;
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root = OB_INVALID_INDEX;
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if (OB_UNLIKELY(!is_inited_)) {
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ret = OB_NOT_INIT;
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LOG_WARN("union find is not initialized", K(ret));
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} else if (x < 0 || x >= parent_.count()) {
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ret = OB_INVALID_INDEX;
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LOG_WARN("invalid index", K(ret));
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} else {
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// compress the height of the tree
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while (parent_.at(x) != x) {
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parent_.at(x) = parent_.at(parent_.at(x));
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x = parent_.at(x);
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}
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root = x;
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}
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return ret;
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}
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int UnionFind::is_connected(int64_t p,
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int64_t q,
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bool &connected)
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{
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int ret = OB_SUCCESS;
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connected = false;
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int64_t root_p = OB_INVALID_INDEX;
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int64_t root_q = OB_INVALID_INDEX;
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if (OB_UNLIKELY(!is_inited_)) {
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ret = OB_NOT_INIT;
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LOG_WARN("union find is not initialized", K(ret));
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} else if (OB_FAIL(find_root(p, root_p))) {
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LOG_WARN("failed to find node", K(ret));
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} else if (OB_FAIL(find_root(q, root_q))) {
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LOG_WARN("failed to find node", K(ret));
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} else {
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connected = (root_p == root_q);
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}
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return ret;
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}
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} // namespace sql
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} // namespace oceanbase
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