int binarySearch(int arr[], int l, int r, int x) { while (l <= r) { int mid = l + (r - l) / 2; if (arr[mid] == x) { return mid; } if (arr[mid] < x) { l = mid + 1; } else { r = mid - 1; } } return -1; }3.分别确定3条路径,满足100%语句覆盖、完全分支覆盖、完全谓词覆盖,并推导出相应路径的路径谓词表达式
时间: 2023-12-20 12:03:50 浏览: 30
1. 100%语句覆盖路径:l=0, r=4, x=2 -> mid=2 -> arr[mid]==x -> return 2
路径谓词表达式:无
2. 完全分支覆盖路径:l=0, r=4, x=2 -> mid=2 -> arr[mid]==x -> return 2
路径谓词表达式:l<=r && (arr[mid]==x || arr[mid]<x)
3. 完全谓词覆盖路径:l=0, r=4, x=2 -> mid=2 -> arr[mid]==x -> return 2
路径谓词表达式:l<=r && (arr[mid]==x || (arr[mid]>=x && r=mid-1) || (arr[mid]<=x && l=mid+1))
相关问题
public class BinarySearch { public static int binarySearch(int[] arr, int target) { int left = 0; int right = arr.length - 1; while (left <= right) { int mid = left + (right - left) / 2; if (arr[mid] == target) { return mid; } else if (arr[mid] < target) { left = mid + 1; } else { right = mid - 1; } } return -1; } public static void main(String[] args) { int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; int target = 7; int index = binarySearch(arr, target); if (index != -1) { System.out.println("Target found at index " + index); } else { System.out.println("Target not found"); } }}
这是一个Java程序,实现了二分查找算法。在main函数中,定义了一个有序数组arr和一个目标值target,然后调用binarySearch函数查找目标值在数组中的位置。如果找到了,则输出"Target found at index "和目标值在数组中的下标;否则输出"Target not found"。
检查语法错误public class Test01 { public static void main(String[] args) { int[] arr = {0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20}; int element = 18; System.out.println(element + "在数组中的索引位置为:" + mid); System.out.println(element + "在数组中的索引位置为:" + -1); } public static int binarySearch(int[] arr,int element) { int min = 0; int max = arr.length - 1; while (true) { int mid = (min + max) / 2; if (element > arr[mid]) { min = mid + 1; } else if (element < arr[mid]) { max = mid - 1; } else { return mid; } if (min > max) { return -1; } } } }
在main方法中,需要调用binarySearch方法获取索引位置,而mid变量未定义。修改为以下代码即可:
```
public class Test01 {
public static void main(String[] args) {
int[] arr = {0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20};
int element = 18;
int index = binarySearch(arr, element);
System.out.println(element + "在数组中的索引位置为:" + index);
if (index == -1) {
System.out.println("元素不在数组中");
}
}
public static int binarySearch(int[] arr, int element) {
int min = 0;
int max = arr.length - 1;
while (true) {
int mid = (min + max) / 2;
if (element > arr[mid]) {
min = mid + 1;
} else if (element < arr[mid]) {
max = mid - 1;
} else {
return mid;
}
if (min > max) {
return -1;
}
}
}
}
```