first init

array/1binary search/704Binary search/kotlin/704.kt

@@ -0,0 +1,43 @@
+
+// （版本二）左闭右闭区间
+class Solution {
+    fun search(nums: IntArray, target: Int): Int {
+        var left = 0
+        var right = nums.size - 1 // [left,right] 右侧为闭区间，right 设置为 nums.size - 1
+        while (left <= right) {
+            val mid = (left + right) / 2
+            if (nums[mid] < target) left = mid + 1
+            else if (nums[mid] > target) right = mid - 1 // 代码的核心，循环中 right 是闭区间，这里也应是闭区间
+            else return mid
+        }
+        return -1 // 没有找到 target ，返回 -1
+    }
+}
+
+class Solution_2 {
+
+    fun search(nums: IntArray, target: Int): Int {
+     var left = 0
+     var right = nums.size // [left,right) 右侧为开区间，
+    while (left < right) {
+        val mid = (left + right) / 2
+        if (nums[mid] < target) left = mid + 1
+        else if (nums[mid] > target) right = mid // 代码的核心，循环中 right 是开区间，这里应是开区间
+        else return mid
+    }
+    return -1 // 没有找到 target ，返回 -1
+    }
+}
+
+// 测试用例
+fun main() {
+    val nums = intArrayOf( 0, 1, 2, 4, 5, 6, 7)
+    val target = 0
+    val solution = Solution()
+    val result = solution.search(nums, target)
+    val solution2 = Solution_2()
+    val result2 = solution2.search(nums, target)
+    println("Solution 1: $result") // 0
+    println("Solution 2: $result2") // 0
+
+}