modify code

MCA算法突击课/第03期/mca_07/Code01_TopologicalSort.java

@@ -14,7 +14,7 @@ import java.io.StreamTokenizer;
 import java.util.ArrayList;
 import java.util.Arrays;
 
-public class Code04_TopologicalSort {
+public class Code01_TopologicalSort {
 
 	public static int MAXN = 200001;
 

MCA算法突击课/第03期/mca_07/Code02_Kruskal.java

@@ -14,7 +14,7 @@ import java.io.PrintWriter;
 import java.io.StreamTokenizer;
 import java.util.Arrays;
 
-public class Code05_Kruskal {
+public class Code02_Kruskal {
 
 	public static int MAXM = 100001;
 

MCA算法突击课/第03期/mca_07/Code03_OptimizeWaterDistributionInVillage.java

@@ -14,7 +14,7 @@ import java.util.Arrays;
 // 连接是双向的
 // 请返回 为所有房子都供水的最低总成本
 // 测试链接 : https://leetcode.cn/problems/optimize-water-distribution-in-a-village/
-public class Code06_OptimizeWaterDistributionInVillage {
+public class Code03_OptimizeWaterDistributionInVillage {
 
 	public static int MAXN = 10010;
 

MCA算法突击课/第03期/mca_07/Code04_NetworkDelayTime.java

@@ -6,7 +6,7 @@ import java.util.PriorityQueue;
 // Dijkstra算法
 // leetcode 743题，可以用这道题来练习Dijkstra算法
 // 测试链接 : https://leetcode.com/problems/network-delay-time
-public class Code07_NetworkDelayTime {
+public class Code04_NetworkDelayTime {
 
 	public static int networkDelayTime(int[][] times, int n, int k) {
 		ArrayList<ArrayList<int[]>> nexts = new ArrayList<>();

MCA算法突击课/第03期/mca_07/Code05_MaximumFrequencyStack.java

@@ -0,0 +1,54 @@
+package 第03期.mca_07;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+// 设计一个类似堆栈的数据结构，将元素推入堆栈，并从堆栈中弹出出现频率最高的元素。
+// 实现 FreqStack 类:
+// FreqStack() 构造一个空的堆栈。
+// void push(int val) 将一个整数 val 压入栈顶。
+// int pop() 删除并返回堆栈中出现频率最高的元素。
+// 如果出现频率最高的元素不只一个，则移除并返回最接近栈顶的元素。
+// 测试链接 : https://leetcode.cn/problems/maximum-frequency-stack/
+public class Code05_MaximumFrequencyStack {
+
+	class FreqStack {
+
+		// 出现的最大次数
+		private int topTimes;
+		// 每层节点
+		private HashMap<Integer, ArrayList<Integer>> cntValues = new HashMap<>();
+		// 每一个数出现了几次
+		private HashMap<Integer, Integer> valueTopTime = new HashMap<>();
+
+		public void push(int val) {
+			// 当前数词频+1
+			valueTopTime.put(val, valueTopTime.getOrDefault(val, 0) + 1);
+			// 当前数是什么词频 5 7次
+			int curTopTimes = valueTopTime.get(val);
+			if (!cntValues.containsKey(curTopTimes)) {
+				cntValues.put(curTopTimes, new ArrayList<>());
+			}
+			ArrayList<Integer> curTimeValues = cntValues.get(curTopTimes);
+			curTimeValues.add(val);
+			topTimes = Math.max(topTimes, curTopTimes);
+		}
+
+		public int pop() {
+			// 最大词频的那一层的链表(动态数组)
+			ArrayList<Integer> topTimeValues = cntValues.get(topTimes);
+			int ans = topTimeValues.remove(topTimeValues.size() - 1);
+			if (topTimeValues.size() == 0) {
+				cntValues.remove(topTimes--);
+			}
+			int times = valueTopTime.get(ans);
+			if (times == 1) {
+				valueTopTime.remove(ans);
+			} else {
+				valueTopTime.put(ans, times - 1);
+			}
+			return ans;
+		}
+	}
+
+}

MCA算法突击课/第03期/mca_07/Code06_InsertDeleteGetRandom.java

@@ -0,0 +1,52 @@
+package 第03期.mca_07;
+
+import java.util.HashMap;
+
+// 测试链接 : https://leetcode.com/problems/insert-delete-getrandom-o1/
+public class Code06_InsertDeleteGetRandom {
+
+	public class RandomizedSet {
+
+		private HashMap<Integer, Integer> keyIndexMap;
+		private HashMap<Integer, Integer> indexKeyMap;
+		private int size;
+
+		public RandomizedSet() {
+			keyIndexMap = new HashMap<Integer, Integer>();
+			indexKeyMap = new HashMap<Integer, Integer>();
+			size = 0;
+		}
+
+		public boolean insert(int val) {
+			if (!keyIndexMap.containsKey(val)) {
+				keyIndexMap.put(val, size);
+				indexKeyMap.put(size++, val);
+				return true;
+			}
+			return false;
+		}
+
+		public boolean remove(int val) {
+			if (keyIndexMap.containsKey(val)) {
+				int deleteIndex = keyIndexMap.get(val);
+				int lastIndex = --size;
+				int lastKey = indexKeyMap.get(lastIndex);
+				keyIndexMap.put(lastKey, deleteIndex);
+				indexKeyMap.put(deleteIndex, lastKey);
+				keyIndexMap.remove(val);
+				indexKeyMap.remove(lastIndex);
+				return true;
+			}
+			return false;
+		}
+
+		public int getRandom() {
+			if (size == 0) {
+				return -1;
+			}
+			int randomIndex = (int) (Math.random() * size);
+			return indexKeyMap.get(randomIndex);
+		}
+	}
+
+}

MCA算法突击课/第03期/mca_07/ReadLine.java

@@ -0,0 +1,19 @@
+package 第03期.mca_07;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class ReadLine {
+
+	public static void main(String[] args) throws IOException {
+		System.out.println("请输入文本");
+		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+		String line = null;
+		while ((line = in.readLine()) != null) {
+			System.out.println(line);
+		}
+		in.close();
+	}
+
+}