redo

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n皇后

src/main/java/cn/whaifree/leetCode/Greedy/LeetCode134.java

@@ -11,11 +11,26 @@ import org.junit.Test;
 public class LeetCode134 {
 
     @Test
-    public void test() {
+    public void test() throws InterruptedException {
-        System.out.println(new Solution().canCompleteCircuit(
+
-                new int[]{5,1,2,3,4},
+        System.out.println("初始化内存 -Xms");
-                new int[]{4,4,1,5,1}
+        System.out.println(Runtime.getRuntime().totalMemory() / 1024 / 1024 + "m");
-        ));
+
+        System.out.println("最大可使用内存 ：");
+        System.out.println(Runtime.getRuntime().freeMemory() / 1024 / 1024 + "m");
+
+        System.out.println("最大堆内存：-Xmx");
+        System.out.println(Runtime.getRuntime().maxMemory() / 1024 / 1024 + "m");
+
+        // -XX+PrintGCDetails
+
+        int[] ints = new int[10000];
+//        Thread.sleep(1000000);
+
+//        System.out.println(new Solution().canCompleteCircuit(
+//                new int[]{5,1,2,3,4},
+//                new int[]{4,4,1,5,1}
+//        ));
 
     }
 

src/main/java/cn/whaifree/leetCode/Greedy/LeetCode406.java

@@ -0,0 +1,66 @@
+package cn.whaifree.leetCode.Greedy;
+
+import org.junit.Test;
+
+import java.util.*;
+import java.util.function.IntFunction;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/2/29 11:52
+ * @注释
+ */
+public class LeetCode406 {
+
+    @Test
+    public void test() throws InterruptedException {
+        int[][] ints = new int[][]{
+                {7,0},{4,4},{7,1},{5,0},{6,1},{5,2}
+        };
+
+        String gc = new String("gc");
+        List<String> list = new LinkedList<>();
+        int i = 0;
+        while (true) {
+            list.add(gc + gc + i++);
+        }
+
+//        for (int[] i : new Solution().reconstructQueue(ints)) {
+//            System.out.println(Arrays.toString(i));
+//        }
+    }
+
+    class Solution {
+        public int[][] reconstructQueue(int[][] people) {
+            // {7,0},{4,4},{7,1},{5,0},{6,1},{5,2}
+            Arrays.sort(people, new Comparator<int[]>() {
+                @Override
+                public int compare(int[] o1, int[] o2) {
+                    if (o1[0] == o2[0]) {
+                        // 身高相同时,前面数量少的在前
+                        return o1[1] - o2[1];
+                    }else {
+                        return o2[0] - o1[0];
+                    }
+                }
+            });
+            for (int[] person : people) {
+                System.out.println(Arrays.toString(person));
+            }
+
+            System.out.println("====");
+
+            // 排序： [[7,0], [7,1], [6,1], [5,0], [5,2]，[4,4]]
+            List<Object> list = new LinkedList<>();
+
+            // 节点i的前面必然都比i高，那么只要把i插入到i[1]对应的位置，必然满足条件
+            for (int[] p : people) {
+                list.add(p[1],p);
+            }
+
+            return list.toArray(new int[people.length][]);
+        }
+    }
+
+}

src/main/java/cn/whaifree/leetCode/Greedy/LeetCode860.java

@@ -23,6 +23,7 @@ public class LeetCode860 {
 
         /**
          * bills[i] 不是 5 就是 10 或是 20
+         *
          * @param bills
          * @return
          */
@@ -55,4 +56,6 @@ public class LeetCode860 {
 
 
     }
+
+
 }

src/main/java/cn/whaifree/leetCode/T.java

@@ -1,5 +1,8 @@
 package cn.whaifree.leetCode;
 
+import java.util.ArrayList;
+import java.util.Random;
+
 /**
  * @version 1.0
  * @Author whai文海
@@ -100,3 +103,28 @@ class VirtualMethodTest {
         fa.show("a");
     }
 }
+
+
+
+class Picture{
+    int number = 0;
+    public Picture() {
+
+    }
+
+    public Picture(int number) {
+        this.number = number;
+    }
+
+    public static void main(String[]args){
+        ArrayList<Picture> list = new ArrayList<>();
+        while(true){
+            try {
+                Thread.sleep(10);
+            } catch (InterruptedException e){
+                e.printStackTrace();
+            }
+            list.add(new Picture(new Random().nextInt(1024*1024)));
+        }
+    }
+}

src/main/java/cn/whaifree/leetCode/Test.java

@@ -2,10 +2,7 @@ package cn.whaifree.leetCode;
 
 import cn.whaifree.leetCode.Tree.LeetCode94;
 
-import java.util.HashMap;
+import java.util.*;
-import java.util.LinkedList;
-import java.util.Map;
-import java.util.PriorityQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -38,6 +35,11 @@ public class Test {
     private int getNumber;
 
 
+
+
+
+
+
     public int minus() {
         localVarl();
         int i = 1;

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode122.java

@@ -0,0 +1,31 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 11:16
+ * @注释
+ */
+public class LeetCode122 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().maxProfit(new int[]{7, 1, 5, 3, 6, 4}));
+    }
+
+    class Solution {
+        public int maxProfit(int[] prices) {
+            int profit = 0;
+            for (int i = 1; i < prices.length; i++) {
+                int sub = prices[i] - prices[i - 1];
+                if (sub > 0) {
+                    profit += sub;
+                }
+            }
+            return profit;
+        }
+    }
+
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode134.java

@@ -0,0 +1,56 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 12:07
+ * @注释
+ */
+public class LeetCode134 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().canCompleteCircuit(new int[]{1, 2, 3, 4, 5}, new int[]{3, 4, 5, 1, 2}));
+        System.out.println(new Solution().canCompleteCircuit(new int[]{5,1,2,3,4}, new int[]{4,4,1,5,1}));
+
+    }
+
+    class Solution {
+        /**
+         * 1. 判断能否循环
+         * 2. 如果一定可以循环，找到第一个能剩下油量的
+         * @param gas
+         * @param cost
+         * @return
+         */
+        public int canCompleteCircuit(int[] gas, int[] cost) {
+            // 计算差值
+            int length = gas.length;
+            int[] rent = new int[length];
+            int rentGas = 0;
+            for (int i = 0; i < length; i++) {
+                rent[i] = gas[i] - cost[i];
+                rentGas += rent[i];
+            }
+            if (rentGas<0){
+                return -1;
+            }
+
+            int have = 0;
+            int resIndex = 0;
+            for (int i = 0; i < length; i++) {
+                have += rent[i];
+                if (have < 0) {
+                    // 油量不够,从下一个点开始
+                    resIndex = (i + 1) % length;
+                    have = 0;
+                }
+            }
+            // [a,b] a内有不够用的时候，b内也有可能有不够用的时候，用index标记
+            return resIndex;
+        }
+
+    }
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode376.java

@@ -0,0 +1,50 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 10:37
+ * @注释
+ */
+public class LeetCode376 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().wiggleMaxLength(new int[]{1, 7, 4, 9, 2, 5}));
+    }
+
+    class Solution {
+        /**
+         * 摆动序列
+         *
+         * @param nums
+         * @return
+         */
+        public int wiggleMaxLength(int[] nums) {
+            if (nums.length == 1) {
+                return 1;
+            }
+
+            // 计算两数差值
+            int curSub = 0;
+            int preSub = 0;
+
+            int res = 1;
+
+            for (int i = 1; i < nums.length; i++) {
+                curSub = nums[i] - nums[i - 1];
+                // preSub = 0 主要让第一次进入循环
+                if ((curSub < 0 && preSub >= 0) || (curSub > 0 && preSub <= 0)) {
+                    res++;
+                    preSub = curSub;
+                }
+            }
+
+            return res;
+
+        }
+    }
+
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode45.java

@@ -0,0 +1,51 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+import javax.annotation.PreDestroy;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 11:36
+ * @注释
+ */
+public class LeetCode45 {
+
+    @Test
+    public void test() {
+        System.out.println(new Solution().jump(new int[]{2,3,1,1,4}));
+    }
+
+    class Solution {
+        /**
+         * 每个index都有一个覆盖区间，每个覆盖区间之间只jump一次
+         * @param nums
+         * @return
+         */
+        public int jump(int[] nums) {
+            if (nums.length == 1) {
+                return 0;
+            }
+
+            int maxCover = 0; // 最大覆盖区间
+            int curCover = 0; // 当前覆盖区间
+            int jumpCount = 0; // 跳跃数
+            for (int i = 0; i < nums.length; i++) {
+                maxCover = Math.max(maxCover, i + nums[i]);
+                // 每次jump count++
+                if (maxCover >= nums.length - 1) {
+                    jumpCount++;
+                    break;
+                }
+                if (i == curCover) {
+                    jumpCount++;
+                    curCover = maxCover; // 到了最后一个，[a,b] a已经执行完了，下次就是b区间中jump一次
+                }
+
+            }
+            return jumpCount;
+        }
+    }
+
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode51.java

@@ -0,0 +1,92 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import cn.whaifree.leetCode.T;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 12:24
+ * @注释
+ */
+public class LeetCode51 {
+
+    @Test
+    public void test() {
+        new Solution().solveNQueens(4);
+    }
+
+
+
+
+    class Solution {
+
+        char[][] map = null;
+        List<List<String>> res = new ArrayList<>();
+
+        /**
+         * 判断是否符合条件
+         * @param n
+         * @return
+         */
+        public List<List<String>> solveNQueens(int n) {
+            map = new char[n][n];
+            for (char[] chars : map) {
+                Arrays.fill(chars, '.');
+            }
+            backTracking(n, 0);
+            return res;
+        }
+
+        public void backTracking(int n,int row) {
+            if (n == row) {
+                List<String> e = new ArrayList<>();
+                for (char[] chars : map) {
+                    StringBuilder s = new StringBuilder();
+                    for (char aChar : chars) {
+                        s.append(aChar);
+                    }
+                    e.add(s.toString());
+                }
+                res.add(e);
+                return;
+            }
+
+            for (int i = 0; i < n; i++) {
+                if (isValid(i, row, n)) {
+                    map[row][i] = 'Q';
+                    backTracking(n, row + 1);
+                    map[row][i] = '.';
+                }
+            }
+
+        }
+
+        boolean isValid(int col, int row,int n) {
+
+            // 往上查找
+            for (int i = row; i >= 0; i--) {
+                if (map[i][col] == 'Q') {
+                    return false;
+                }
+            }
+            // 左上45 这里不检查本节点可以提升很大的效率
+            for (int i = col-1, j = row-1; i >= 0 && j >= 0; i--, j--) {
+                if (map[j][i] == 'Q') {
+                    return false;
+                }
+            }
+            // 右上45
+            for (int i = col + 1, j = row - 1; i < n && j >= 0; i++, j--) {
+                if (map[j][i] == 'Q') {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode53.java

@@ -0,0 +1,39 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 11:01
+ * @注释
+ */
+public class LeetCode53 {
+
+    @Test
+    public void test(
+    ) {
+        System.out.println(new Solution().maxSubArray(new int[]{-2,-1}));
+    }
+
+    class Solution {
+        /**
+         * 一旦加的那个区间为负，只会拖累后面的串，从下一个重加
+         */
+        public int maxSubArray(int[] nums) {
+            if (nums.length == 1) {
+                return nums[0];
+            }
+            int maxSum = Integer.MIN_VALUE;
+            int curSum = 0;
+            for (int i = 0; i < nums.length; i++) {
+                curSum += nums[i];
+                maxSum = Math.max(curSum, maxSum);
+                if (curSum < 0) {
+                    curSum = 0;
+                }
+            }
+            return maxSum;
+        }
+    }
+}

src/main/java/cn/whaifree/redo/redo_24_3_1/LeetCode55.java

@@ -0,0 +1,34 @@
+package cn.whaifree.redo.redo_24_3_1;
+
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/3/1 11:21
+ * @注释
+ */
+public class LeetCode55 {
+    @Test
+    public void test() {
+        System.out.println(new Solution().canJump(new int[]{2,3,1,1,4}));
+    }
+
+    class Solution {
+        public boolean canJump(int[] nums) {
+            if (nums.length == 1) {
+                return true;
+            }
+
+            int maxCover = 0;
+            for (int i = 0; i <= maxCover; i++) {
+                maxCover = Math.max(maxCover, i + nums[i]);
+                if (maxCover >= nums.length - 1) {
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+
+}