添加binarysearch.js

Author: zhenqiang

code/search/binarysearch.js

@@ -0,0 +1,29 @@
+function binarySearch(arr, target) {
+    if (!Array.isArray(arr)) return arr;
+
+    arr.sort((l, r) => l - r);
+
+    let left = 0;
+    let right = arr.length - 1;
+    let middle;
+
+    while (left <= right) {
+        middle = left + parseInt((right - left) / 2);
+
+        if (arr[middle] < target) {
+            left = middle + 1;
+        } else if (arr[middle] > target) {
+            right = middle - 1;
+        } else {
+            return middle;
+        }
+    }
+
+    return -1;
+}
+
+console.log(binarySearch([1, 2, 5], 5));
+console.log(binarySearch([1], 5));
+console.log(binarySearch([1, 5], 1));
+console.log(binarySearch([1, 5], 5));
+console.log(binarySearch([]));