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Merge pull request #2336 from deanbear/main

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手写跳表删除逻辑 bugfix
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Guide 2024-03-23 10:56:31 +08:00 committed by GitHub
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1 changed files with 20 additions and 20 deletions
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docs/database/redis/redis-skiplist.md
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@ -233,7 +233,7 @@ private int randomLevel() {
/** /**
* 默认情况下的高度为1，即只有自己一个节点 * 默认情况下的高度为1，即只有自己一个节点
*/ */
private int leveCount = 1; private int levelCount = 1;
/** /**
* 跳表最底层的节点，即头节点 * 跳表最底层的节点，即头节点
@ -271,9 +271,9 @@ public void add(int value) {
maxOfMinArr[i].forwards[i] = newNode; maxOfMinArr[i].forwards[i] = newNode;
} }
//如果当前newNode高度大于跳表最高高度则更新leveCount //如果当前newNode高度大于跳表最高高度则更新levelCount
if (leveCount < level) { if (levelCount < level) {
leveCount = level; levelCount = level;
} }
} }
@ -299,7 +299,7 @@ public void add(int value) {
public Node get(int value) { public Node get(int value) {
Node p = h; Node p = h;
//找到小于value的最大值 //找到小于value的最大值
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
while (p.forwards[i] != null && p.forwards[i].data < value) { while (p.forwards[i] != null && p.forwards[i].data < value) {
p = p.forwards[i]; p = p.forwards[i];
} }
@ -334,8 +334,8 @@ public Node get(int value) {
public void delete(int value) { public void delete(int value) {
Node p = h; Node p = h;
//找到各级节点小于value的最大值 //找到各级节点小于value的最大值
Node[] updateArr = new Node[leveCount]; Node[] updateArr = new Node[levelCount];
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
while (p.forwards[i] != null && p.forwards[i].data < value) { while (p.forwards[i] != null && p.forwards[i].data < value) {
p = p.forwards[i]; p = p.forwards[i];
} }
@ -344,7 +344,7 @@ public void delete(int value) {
//查看原始层节点前驱是否等于value，若等于则说明存在要删除的值 //查看原始层节点前驱是否等于value，若等于则说明存在要删除的值
if (p.forwards[0] != null && p.forwards[0].data == value) { if (p.forwards[0] != null && p.forwards[0].data == value) {
//从最高级索引开始查看其前驱是否等于value，若等于则将当前节点指向value节点的后继节点 //从最高级索引开始查看其前驱是否等于value，若等于则将当前节点指向value节点的后继节点
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
if (updateArr[i].forwards[i] != null && updateArr[i].forwards[i].data == value) { if (updateArr[i].forwards[i] != null && updateArr[i].forwards[i].data == value) {
updateArr[i].forwards[i] = updateArr[i].forwards[i].forwards[i]; updateArr[i].forwards[i] = updateArr[i].forwards[i].forwards[i];
} }
@ -352,8 +352,8 @@ public void delete(int value) {
} }
//从最高级开始查看是否有一级索引为空，若为空则层级减1 //从最高级开始查看是否有一级索引为空，若为空则层级减1
while (leveCount > 1 && h.forwards[leveCount] == null) { while (levelCount > 1 && h.forwards[levelCount - 1] == null) {
leveCount--; levelCount--;
} }
} }
@ -379,7 +379,7 @@ public class SkipList {
/** /**
* 默认情况下的高度为1，即只有自己一个节点 * 默认情况下的高度为1，即只有自己一个节点
*/ */
private int leveCount = 1; private int levelCount = 1;
/** /**
* 跳表最底层的节点，即头节点 * 跳表最底层的节点，即头节点
@ -436,9 +436,9 @@ public class SkipList {
maxOfMinArr[i].forwards[i] = newNode; maxOfMinArr[i].forwards[i] = newNode;
} }
//如果当前newNode高度大于跳表最高高度则更新leveCount //如果当前newNode高度大于跳表最高高度则更新levelCount
if (leveCount < level) { if (levelCount < level) {
leveCount = level; levelCount = level;
} }
} }
@ -463,7 +463,7 @@ public class SkipList {
public Node get(int value) { public Node get(int value) {
Node p = h; Node p = h;
//找到小于value的最大值 //找到小于value的最大值
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
while (p.forwards[i] != null && p.forwards[i].data < value) { while (p.forwards[i] != null && p.forwards[i].data < value) {
p = p.forwards[i]; p = p.forwards[i];
} }
@ -484,8 +484,8 @@ public class SkipList {
public void delete(int value) { public void delete(int value) {
Node p = h; Node p = h;
//找到各级节点小于value的最大值 //找到各级节点小于value的最大值
Node[] updateArr = new Node[leveCount]; Node[] updateArr = new Node[levelCount];
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
while (p.forwards[i] != null && p.forwards[i].data < value) { while (p.forwards[i] != null && p.forwards[i].data < value) {
p = p.forwards[i]; p = p.forwards[i];
} }
@ -494,7 +494,7 @@ public class SkipList {
//查看原始层节点前驱是否等于value，若等于则说明存在要删除的值 //查看原始层节点前驱是否等于value，若等于则说明存在要删除的值
if (p.forwards[0] != null && p.forwards[0].data == value) { if (p.forwards[0] != null && p.forwards[0].data == value) {
//从最高级索引开始查看其前驱是否等于value，若等于则将当前节点指向value节点的后继节点 //从最高级索引开始查看其前驱是否等于value，若等于则将当前节点指向value节点的后继节点
for (int i = leveCount - 1; i >= 0; i--) { for (int i = levelCount - 1; i >= 0; i--) {
if (updateArr[i].forwards[i] != null && updateArr[i].forwards[i].data == value) { if (updateArr[i].forwards[i] != null && updateArr[i].forwards[i].data == value) {
updateArr[i].forwards[i] = updateArr[i].forwards[i].forwards[i]; updateArr[i].forwards[i] = updateArr[i].forwards[i].forwards[i];
} }
@ -502,8 +502,8 @@ public class SkipList {
} }
//从最高级开始查看是否有一级索引为空，若为空则层级减1 //从最高级开始查看是否有一级索引为空，若为空则层级减1
while (leveCount > 1 && h.forwards[leveCount] == null) { while (levelCount > 1 && h.forwards[levelCount - 1] == null) {
leveCount--; levelCount--;
} }
} }