1 files changed, 33 insertions, 0 deletions
diff --git a/tests/sysy_lvX/binary_search.sy b/tests/sysy_lvX/binary_search.sy
new file mode 100644
index 0000000..97907ee
--- /dev/null
+++ b/tests/sysy_lvX/binary_search.sy
@@ -0,0 +1,33 @@
+int BinSearch(int arr[],int len,int key)                          //折半查找法（二分法）
+{
+	int low=0;                         //定义初始最小
+	int high=len-1;                 //定义初始最大
+	int mid;                            //定义中间值
+	while(low<=high)
+	{
+		mid=(low+high)/2;              //找中间值
+		if(key==arr[mid])               //判断min与key是否相等
+			return mid;    
+		if(key>arr[mid])             //如果key>mid  则新区间为[mid+1,high]
+			low=mid+1;
+		else                                       //如果key<mid  则新区间为[low,mid-1]
+			high=mid-1;
+	}
+	return -1;                             //如果数组中无目标值key，则返回 -1 ；
+}
+int main()
+{
+	int arr2[100];
+    int n;
+    int i = 0;
+    n = getint();
+    while(i<n){
+        arr2[i] = getint();
+        i = i + 1;
+    }
+    n = BinSearch(arr2,n,9);
+    putint(n);
+	return 0;
+}
+
+