diff --git a/src/main/java/cn/whaifree/leetCode/LinkedList/LCR155.java b/src/main/java/cn/whaifree/LCR/LCR155.java similarity index 98% rename from src/main/java/cn/whaifree/leetCode/LinkedList/LCR155.java rename to src/main/java/cn/whaifree/LCR/LCR155.java index 2182ed9..5e4e956 100644 --- a/src/main/java/cn/whaifree/leetCode/LinkedList/LCR155.java +++ b/src/main/java/cn/whaifree/LCR/LCR155.java @@ -1,4 +1,4 @@ -package cn.whaifree.leetCode.LinkedList; +package cn.whaifree.LCR; import org.junit.Test; diff --git a/src/main/java/cn/whaifree/leetCode/Graph/LeetCode207.java b/src/main/java/cn/whaifree/leetCode/Graph/LeetCode207.java new file mode 100644 index 0000000..2cb2142 --- /dev/null +++ b/src/main/java/cn/whaifree/leetCode/Graph/LeetCode207.java @@ -0,0 +1,100 @@ +package cn.whaifree.leetCode.Graph; + +import org.junit.Test; + +import java.util.*; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/9/16 0:02 + * @注释 + */ +public class LeetCode207 { + + @Test + public void test() { + int numCourses = 4; + int[][] prerequisites = {{1, 0},{0,2},{1,3}}; + System.out.println(new Solution().canFinish(numCourses, prerequisites)); + } + class Solution { + public boolean canFinish(int numCourses, int[][] prerequisites) { + List> graph = new ArrayList<>(); + + for (int i = 0; i < numCourses; i++) { + graph.add(new ArrayList<>()); + } + + // 统计入度个数 + int[] inGre = new int[numCourses]; + for (int i = 0; i < prerequisites.length; i++) { + int course = prerequisites[i][0]; + int preCourse = prerequisites[i][1]; + graph.get(preCourse).add(course); + inGre[course]++; + } + + // 对所有入度为0的进入队列 + Deque queue = new ArrayDeque<>(); + for (int i = 0; i < numCourses; i++) { + if (inGre[i] == 0) { + queue.add(i); + } + } + // 出对，并去边 + int exeCount = 0; + while (!queue.isEmpty()) { + Integer pop = queue.pop(); + exeCount++; + // 遍历这个pop点的出边 + List popOut = graph.get(pop); + for (int i = 0; i < popOut.size(); i++) { + int deleteSideNode = popOut.get(i); + inGre[deleteSideNode]--; + if (inGre[deleteSideNode] == 0) { + queue.add(deleteSideNode); + } + } + } + // 如果队列中没有元素了，但还有边，返回false + return exeCount == numCourses; + } + } + + + class Solution1 { + public boolean canFinish(int numCourses, int[][] prerequisites) { + // 统计入度个数 + int[] map = new int[2000]; + for (int i = 0; i < prerequisites.length; i++) { + map[prerequisites[i][0]]++; + } + // 对所有入度为0的进入队列 + Deque queue = new ArrayDeque<>(); + for (int i = 0; i < numCourses; i++) { + if (map[i] == 0) { + queue.add(i); + } + } + // 出对，并去边 + int exeCount = 0; + while (!queue.isEmpty()) { + Integer pop = queue.pop(); + exeCount++; + // 遍历所有的边 + for (int i = 0; i < prerequisites.length; i++) { + if (prerequisites[i][1] == pop) { + int deleteSideNode = prerequisites[i][0]; + map[deleteSideNode]--; + if (map[deleteSideNode] == 0) { + queue.add(deleteSideNode); + } + } + } + } + // 如果队列中没有元素了，但还有边，返回false + return exeCount == numCourses; + } + } +} diff --git a/src/main/java/cn/whaifree/leetCode/Graph/LeetCode210.java b/src/main/java/cn/whaifree/leetCode/Graph/LeetCode210.java new file mode 100644 index 0000000..b7b2858 --- /dev/null +++ b/src/main/java/cn/whaifree/leetCode/Graph/LeetCode210.java @@ -0,0 +1,98 @@ +package cn.whaifree.leetCode.Graph; + +import org.junit.Test; + +import java.util.*; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/9/16 0:44 + * @注释 + */ +public class LeetCode210 { + @Test + public void test() { + int[][] prerequisites = {{1,0},{2,0},{3,1},{3,2}}; + int[] res = new Solution().findOrder(4, prerequisites); + System.out.println(Arrays.toString(res)); + } + + public int[] findOrder(int numCourses, int[][] prerequisites) { + if (numCourses == 0) return new int[0]; + int[] inDegrees = new int[numCourses]; + + + // 建立入度表 + for (int[] p : prerequisites) { + inDegrees[p[0]]++; // 记录每个节点的入度 + } + // 入度为0的节点队列 + Queue queue = new LinkedList<>(); + for (int i = 0; i < inDegrees.length; i++) { + if (inDegrees[i] == 0) queue.offer(i); // 入度为 0 的节点可以进行执行 + } + int count = 0; // 记录可以执行的任务数 + int[] res = new int[numCourses]; // 完整拓扑排序的执行过程 + + // 根据提供的可以执行的任务（入度为 0），删除入度为 0 的节点 + while (!queue.isEmpty()){ + int curr = queue.poll(); // 拿到一个可以执行的任务 + res[count++] = curr; // 这个任务可以执行，作为下一次执行的节点 + for (int[] p : prerequisites) { + if (p[1] == curr){ // {a,b} 表示 a 依赖 b b-->a + inDegrees[p[0]]--; + if (inDegrees[p[0]] == 0) queue.offer(p[0]); + } + } + } + if (count == numCourses) return res; + return new int[0]; + } + + + class Solution { + public int[] findOrder(int numCourses, int[][] prerequisites) { + List> graph = new ArrayList<>(); + for (int i = 0; i < numCourses; i++) { + graph.add(new ArrayList<>()); + } + int[] inGre = new int[numCourses]; + + Deque deque = new LinkedList<>(); + for (int[] prerequisite : prerequisites) { + int course = prerequisite[0]; + int pre = prerequisite[1]; + inGre[course]++; + graph.get(pre).add(course); + } + + for (int i = 0; i < inGre.length; i++) { + if (inGre[i] == 0) { + deque.add(i); + } + } + + int exec = 0; + int[] res = new int[numCourses]; + while (!deque.isEmpty()) { + Integer exe = deque.pop(); + res[exec] = exe; + exec++; + List in = graph.get(exe); + for (int into = 0; into < in.size(); into++) { + Integer intoNode = in.get(into); + inGre[intoNode]--; + if (inGre[intoNode] == 0) { + deque.add(intoNode); + } + } + } + + if (numCourses == exec) { + return res; + } + return new int[0]; + } + } +} diff --git a/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode583.java b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode583.java new file mode 100644 index 0000000..cdff5c9 --- /dev/null +++ b/src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode583.java @@ -0,0 +1,56 @@ +package cn.whaifree.redo.redo_all_240721; + +import org.junit.Test; + +/** + * @version 1.0 + * @Author whai文海 + * @Date 2024/9/16 1:01 + * @注释 + */ +public class LeetCode583 { + + @Test + public void test() { + String word1 = "leetcode"; + String word2 = "etco"; + System.out.println(new Solution().minDistance(word1, word2)); + } + + class Solution { + + public int minDistance(String word1, String word2) { + char[] w1 = word1.toCharArray(); + char[] w2 = word2.toCharArray(); + int[][] dp = new int[w1.length + 1][w2.length + 1]; + for (int i = 0; i <= w2.length; i++) { + dp[0][i] = i; + } + for (int j = 0; j <= w1.length; j++) { + dp[j][0] = j; + } + /** + * '' s e a + * '' 0 1 2 3 + * e 1 2 1 2 不配 左边|上 +1 配 对i-1 j-1 + * a 2 3 2 + * t 3 + * + * @param word1 + * @param word2 + * @return + */ + + for (int i = 0; i < w1.length; i++) { + for (int j = 0; j < w2.length; j++) { + if (w1[i] == w2[j]) { + dp[i + 1][j + 1] = dp[i][j]; + }else { + dp[i + 1][j + 1] = Math.min(dp[i][j + 1], dp[i + 1][j]) + 1; + } + } + } + return dp[w1.length][w2.length]; + } + } +}