Merge branch 'master' into 18_hashtable

Author: Liam0205

.gitignore

@@ -25,3 +25,6 @@ hs_err_pid*
 # editor files
 .vscode
 .*.swp
+
+# WebStorm
+.idea/

c-cpp/15_bsearch/bsearch_c/sqrt.c

@@ -0,0 +1,53 @@
+/*************************************************************************
+ > File Name: sqrt.c
+ > Author:  jinshaohui
+ > Mail:    [email protected]
+ > Time:    18-10-31
+ > Desc:    
+ ************************************************************************/
+#include<stdio.h>
+#include<string.h>
+#include<stdlib.h>
+#include<assert.h>
+
+
+/*求解精度设置*/
+#define E 0.000001 
+double mybsearch(double num)
+{
+	double start = 1.0;
+	double end = num;
+    double mid = 0.0;
+	while(1)
+	{
+	    mid = (start + end)/2;
+        if(((mid*mid - num) <= E) && ((mid*mid - num) >= -E))
+		{
+			return mid;
+		}
+
+		if ((mid*mid - num) > E)
+		{
+			end = mid;
+		}
+		else
+		{
+			start = mid;
+		}
+ 	}
+
+	return 0;
+}
+	
+
+int main()
+{
+	double num = 0.0;
+
+	/*这里需要注意：double的输入方式*/
+	scanf("%lf",&num);
+	printf("\r\n num %lf的平方根是%lf",num,mybsearch(num));
+
+	return 0;
+}
+

c-cpp/16_bsearch/bsearch.c

@@ -0,0 +1,190 @@
+/*************************************************************************
+ > File Name: bsearch.c
+ > Author:  jinshaohui
+ > Mail:    [email protected]
+ > Time:    18-10-21
+ > Desc:    
+ ************************************************************************/
+#include<stdio.h>
+#include<stdlib.h>
+#include<assert.h>
+
+/*二分查找算法的变形问题
+ *1、查找第一个等于给定数值的元素
+ *2、查找最后一个等于给定数值的元素
+ *3、查找第一个大于等于给定数值的元素
+ *4、查找第一个小于等于给定数值的元素
+ * */
+
+
+ /*1、查找第一个等于给定数值的元素*/
+int mybsearch_1(int a[],int size,int value)
+{
+	int mid = 0;
+	int left = 0;
+	int right = size - 1;
+
+	while(left <= right)
+	{
+		/*防止size数量太大是，（left + right）数据翻转，导致问题*/
+		mid = left + ((right - left)>>1);
+
+		if (a[mid] < value)
+		{
+			left = mid + 1;
+		}
+		else if (a[mid] > value)
+		{
+			right = mid - 1;
+		}
+		else
+		{
+			if ((mid == 0) || (a[mid - 1] != value))
+			{
+                return mid;
+			}
+			else
+			{
+				right = mid - 1;
+			}
+		}
+	}
+
+	return -1;
+}
+
+ /*2、查找最后一个等于给定数值的元素*/
+int mybsearch_2(int a[],int size,int value)
+{
+	int mid = 0;
+	int left = 0;
+	int right = size - 1;
+
+	while(left <= right)
+	{
+		/*防止size数量太大是，（left + right）数据翻转，导致问题*/
+		mid = left + ((right - left)>>1);
+
+		if (a[mid] < value)
+		{
+			left = mid + 1;
+		}
+		else if (a[mid] > value)
+		{
+			right = mid - 1;
+		}
+		else
+		{
+			if ((mid == (size - 1)) || (a[mid + 1] != value))
+			{
+                return mid;
+			}
+			else
+			{
+				left = mid + 1;
+			}
+		}
+	}
+
+	return -1;
+}
+ /*3、查找第一个大于等于给定数值的元素*/
+int mybsearch_3(int a[],int size,int value)
+{
+	int mid = 0;
+	int left = 0;
+	int right = size - 1;
+
+	while(left <= right)
+	{
+		/*防止size数量太大是，（left + right）数据翻转，导致问题*/
+		mid = left + ((right - left)>>1);
+
+		if (a[mid] < value)
+		{
+			left = mid + 1;
+		}
+		else
+		{
+			/*a[mid] >= value 当mid==0 或者a[mid-1] > value 说明是第一个大于等于value*/
+			if ((mid == 0) || (a[mid - 1] < value))
+			{
+                return mid;
+			}
+			else
+			{
+				right = mid - 1;
+			}
+		}
+	}
+
+	return -1;
+}
+
+ /*4、查找第一个小于等于给定数值的元素*/
+int mybsearch_4(int a[],int size,int value)
+{
+	int mid = 0;
+	int left = 0;
+	int right = size - 1;
+
+	while(left <= right)
+	{
+		/*防止size数量太大是，（left + right）数据翻转，导致问题*/
+		mid = left + ((right - left)>>1);
+
+		if (a[mid] > value)
+		{
+			right = mid - 1;
+		}
+		else
+		{
+			/*a[mid] <= value 时，当前mid == size -1 数组中最大的数值；
+			 *                    或者a[mid + 1] 大于vlaue，就是mid就第一个小于等于value*/
+			if ((mid == (size - 1)) || (a[mid + 1] > value))
+			{
+                return mid;
+			}
+			else
+			{
+				left = mid + 1;
+			}
+		}
+	}
+
+	return -1;
+}
+int main()
+{
+	int a[10] = {5,6,6,9,10,11,11,22,33,33};
+    int data = 0;
+	int i = 0;
+	int res =0;
+
+	printf("\r\n");
+    for(i = 0; i < 10 ; i++)
+	{
+		printf("%d ",a[i]);
+	}
+	printf("\r\n");
+	printf("\r\n输入一个整数");
+	scanf("%d",&data);
+    res = mybsearch_1(a,10,data);
+	printf("第一个等于data[%d]，下标是%d",data,res);
+	
+	printf("\r\n输入一个整数");
+	scanf("%d",&data);
+    res = mybsearch_2(a,10,data);
+	printf("最后一个等于data[%d]，下标是%d",data,res);
+
+	printf("\r\n输入一个整数");
+	scanf("%d",&data);
+    res = mybsearch_2(a,10,data);
+	printf("第一个大于等于data[%d]，下标是%d",data,res);
+
+	printf("\r\n输入一个整数");
+	scanf("%d",&data);
+    res = mybsearch_2(a,10,data);
+	printf("第一个小等于data[%d]，下标是%d",data,res);
+	return;
+}