modify code on class

src/class01/Code01_SelectionSort.java

@@ -8,11 +8,10 @@ public class Code01_SelectionSort {
 		if (arr == null || arr.length < 2) {
 			return;
 		}
-		// 0 ~ N-1
-		// 1~n-1
-		// 2
-		for (int i = 0; i < arr.length - 1; i++) { // i ~ N-1
-			// 最小值在哪个位置上  i～n-1
+		// 0 ~ N-1  找到最小值，在哪，放到0位置上
+		// 1 ~ n-1  找到最小值，在哪，放到1 位置上
+		// 2 ~ n-1  找到最小值，在哪，放到2 位置上
+		for (int i = 0; i < arr.length - 1; i++) {
 			int minIndex = i;
 			for (int j = i + 1; j < arr.length; j++) { // i ~ N-1 上找最小值的下标 
 				minIndex = arr[j] < arr[minIndex] ? j : minIndex;

src/class01/Code03_InsertionSort.java

@@ -8,8 +8,7 @@ public class Code03_InsertionSort {
 		if (arr == null || arr.length < 2) {
 			return;
 		}
-		// 0~0 有序的
-		// 0~i 想有序
+		// 不只1个数
 		for (int i = 1; i < arr.length; i++) { // 0 ~ i 做到有序
 			for (int j = i - 1; j >= 0 && arr[j] > arr[j + 1]; j--) {
 				swap(arr, j, j + 1);
@@ -36,8 +35,7 @@ public class Code03_InsertionSort {
 		// (int)(Math.random() * N) -> [0,N-1] 所有的整数，等概率返回一个
 		int[] arr = new int[(int) ((maxSize + 1) * Math.random())]; // 长度随机
 		for (int i = 0; i < arr.length; i++) {
-			arr[i] = (int) ((maxValue + 1) * Math.random()) 
-					- (int) (maxValue * Math.random());
+			arr[i] = (int) ((maxValue + 1) * Math.random()) - (int) (maxValue * Math.random());
 		}
 		return arr;
 	}
@@ -91,14 +89,19 @@ public class Code03_InsertionSort {
 		int maxValue = 100;// 值：-100～100
 		boolean succeed = true;
 		for (int i = 0; i < testTime; i++) {
-			int[] arr1 = generateRandomArray(maxSize, maxValue);
-			int[] arr2 = copyArray(arr1);
+			int[] arr = generateRandomArray(maxSize, maxValue);
+			int[] arr1 = copyArray(arr);
+			int[] arr2 = copyArray(arr);
 			insertionSort(arr1);
 			comparator(arr2);
 			if (!isEqual(arr1, arr2)) {
 				// 打印arr1
 				// 打印arr2
 				succeed = false;
+				for (int j = 0; j < arr.length; j++) {
+					System.out.print(arr[j] + " ");
+				}
+				System.out.println();
 				break;
 			}
 		}

src/class01/Code04_BSExist.java

@@ -12,12 +12,8 @@ public class Code04_BSExist {
 		int R = sortedArr.length - 1;
 		int mid = 0;
 		// L..R
-		while (L < R) {
-			// mid = (L+R) / 2;
-			// L 10亿  R 18亿
-			// mid = L + (R - L) / 2
-			// N / 2    N >> 1
-			mid = L + ((R - L) >> 1); // mid = (L + R) / 2
+		while (L < R) { // L..R 至少两个数的时候
+			mid = L + ((R - L) >> 1);
 			if (sortedArr[mid] == num) {
 				return true;
 			} else if (sortedArr[mid] > num) {

src/class01/Code05_BSNearLeft.java

@@ -9,7 +9,7 @@ public class Code05_BSNearLeft {
 		int L = 0;
 		int R = arr.length - 1;
 		int index = -1; // 记录最左的对号
-		while (L <= R) {
+		while (L <= R) { // 至少一个数的时候
 			int mid = L + ((R - L) >> 1);
 			if (arr[mid] >= value) {
 				index = mid;

src/class01/Code07_EvenTimesOddTimes.java

@@ -17,12 +17,14 @@ public class Code07_EvenTimesOddTimes {
 		for (int i = 0; i < arr.length; i++) {
 			eor ^= arr[i];
 		}
-		// eor = a ^ b
+		// a 和 b是两种数
 		// eor != 0
-		// eor必然有一个位置上是1
-		// 0110010000
-		// 0000010000
-		int rightOne = eor & (~eor + 1); // 提取出最右的1
+		// eor最右侧的1，提取出来
+		// eor :     00110010110111000
+		// rightOne :00000000000001000
+		int rightOne = eor & (-eor); // 提取出最右的1
+		
+		
 		int onlyOne = 0; // eor'
 		for (int i = 0 ; i < arr.length;i++) {
 			//  arr[1] =  111100011110000

src/class01/Code08_KM.java

@@ -0,0 +1,130 @@
+package class01;
+
+import java.util.HashMap;
+import java.util.HashSet;
+
+public class Code08_KM {
+
+	public static int test(int[] arr, int k, int m) {
+		HashMap<Integer, Integer> map = new HashMap<>();
+		for (int num : arr) {
+			if (map.containsKey(num)) {
+				map.put(num, map.get(num) + 1);
+			} else {
+				map.put(num, 1);
+			}
+		}
+		for (int num : map.keySet()) {
+			if (map.get(num) == k) {
+				return num;
+			}
+		}
+		return -1;
+	}
+
+	// 请保证arr中，只有一种数出现了K次，其他数都出现了M次
+	public static int onlyKTimes(int[] arr, int k, int m) {
+		int[] t = new int[32];
+		// t[0] 0位置的1出现了几个
+		// t[i] i位置的1出现了几个
+		for (int num : arr) {
+			for (int i = 0; i <= 31; i++) {
+				t[i] += (num >> i) & 1;
+			}
+		}
+		int ans = 0;
+		for (int i = 0; i < 32; i++) {
+			if (t[i] % m == 0) {
+				continue;
+			}
+			if (t[i] % m == k) {
+				ans |= (1 << i);
+			} else {
+				return -1;
+			}
+		}
+		if (ans == 0) {
+			int count = 0;
+			for (int num : arr) {
+				if (num == 0) {
+					count++;
+				}
+			}
+			if (count != k) {
+				return -1;
+			}
+		}
+		return ans;
+	}
+
+	public static int[] randomArray(int maxKinds, int range, int k, int m) {
+		int ktimeNum = randomNumber(range);
+		// 真命天子出现的次数
+		int times = Math.random() < 0.5 ? k : ((int) (Math.random() * (m - 1)) + 1);
+		// 2
+		int numKinds = (int) (Math.random() * maxKinds) + 2;
+		// k * 1 + (numKinds - 1) * m
+		int[] arr = new int[times + (numKinds - 1) * m];
+		int index = 0;
+		for (; index < times; index++) {
+			arr[index] = ktimeNum;
+		}
+		numKinds--;
+		HashSet<Integer> set = new HashSet<>();
+		set.add(ktimeNum);
+		while (numKinds != 0) {
+			int curNum = 0;
+			do {
+				curNum = randomNumber(range);
+			} while (set.contains(curNum));
+			set.add(curNum);
+			numKinds--;
+			for (int i = 0; i < m; i++) {
+				arr[index++] = curNum;
+			}
+		}
+		// arr 填好了
+		for (int i = 0; i < arr.length; i++) {
+			// i 位置的数，我想随机和j位置的数做交换
+			int j = (int) (Math.random() * arr.length);// 0 ~ N-1
+			int tmp = arr[i];
+			arr[i] = arr[j];
+			arr[j] = tmp;
+		}
+		return arr;
+	}
+
+	// [-range, +range]
+	public static int randomNumber(int range) {
+		return ((int) (Math.random() * range) + 1) - ((int) (Math.random() * range) + 1);
+	}
+
+	public static void main(String[] args) {
+		int kinds = 4;
+		int range = 200;
+		int testTime = 100000;
+		int max = 9;
+		System.out.println("测试开始");
+		for (int i = 0; i < testTime; i++) {
+			int a = (int) (Math.random() * max) + 1; // a 1 ~ 9
+			int b = (int) (Math.random() * max) + 1; // b 1 ~ 9
+			int k = Math.min(a, b);
+			int m = Math.max(a, b);
+			// k < m
+			if (k == m) {
+				m++;
+			}
+			int[] arr = randomArray(kinds, range, k, m);
+			int ans1 = test(arr, k, m);
+			int ans2 = onlyKTimes(arr, k, m);
+			if (ans1 != ans2) {
+				System.out.println(ans1);
+				System.out.println(ans2);
+				System.out.println("出错了！");
+			}
+		}
+		System.out.println("测试结束");
+
+	}
+
+}

src/class01/Test.java

@@ -3,8 +3,17 @@ package class01;
 public class Test {
 	
 	public static void main(String[] args) {
-		int a = 6;
-		int b = 6;
+
+		
+		
+		
+		
+		
+		int a = 16;
+		int b = 603;
+		
+		System.out.println(a);
+		System.out.println(b);
 		
 		
 		a = a ^ b;
@@ -20,6 +29,23 @@ public class Test {
 		
 		int[] arr = {3,1,100};
 		
+		int i = 0;
+		int j = 0;
+		
+		arr[i] = arr[i] ^ arr[j];
+		arr[j] = arr[i] ^ arr[j];
+		arr[i] = arr[i] ^ arr[j];
+		
+		System.out.println(arr[i] + " , " + arr[j]);
+		
+		
+		
+		
+		
+		
+		
+		
+		
 		System.out.println(arr[0]);
 		System.out.println(arr[2]);