From 4f36e60af52b4bfd1a51a1074a5a954f3210c2bd Mon Sep 17 00:00:00 2001
From: yko-git <yko.iwata@gmail.com>
Date: Mon, 11 Mar 2024 11:49:46 +0900
Subject: [PATCH 1/4] fix 004_algorithm/002_search linearSearch/binarySearch

---
 004_algorithm/002_search.js | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/004_algorithm/002_search.js b/004_algorithm/002_search.js
index 86ee651..e8786bc 100644
--- a/004_algorithm/002_search.js
+++ b/004_algorithm/002_search.js
@@ -1,4 +1,3 @@
-
 /**
  *  2.3.1 リニアサーチ
  *
@@ -11,7 +10,15 @@
  *    [5, 3, 2, 1], 6 => -1
  */
 
-function linearSearch (array, target) {
+function linearSearch(array, target) {
+  let index = -1;
+
+  for (let i = 0; i < array.length; i++) {
+    if (array[i] === target) {
+      index = i;
+    }
+  }
+  return index;
 }
 
 /**
@@ -24,10 +31,12 @@ function linearSearch (array, target) {
  *    [1, 2, 3, 4] 5 => -1
  */
 
-function binarySearch (array, target) {
+function binarySearch(array, target) {
+  let arrayLength = array.length / 2;
+  console.log(arrayLength);
 }
 
 module.exports = {
   linearSearch,
-  binarySearch
-}
+  binarySearch,
+};

From a52a8f39adec7a3c1d4ba80de8e84c8977549551 Mon Sep 17 00:00:00 2001
From: yko-git <yko.iwata@gmail.com>
Date: Tue, 12 Mar 2024 12:22:13 +0900
Subject: [PATCH 2/4] fix 002_search linearSearch/binarySearch

---
 004_algorithm/002_search.js | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/004_algorithm/002_search.js b/004_algorithm/002_search.js
index e8786bc..68863d0 100644
--- a/004_algorithm/002_search.js
+++ b/004_algorithm/002_search.js
@@ -11,14 +11,12 @@
  */
 
 function linearSearch(array, target) {
-  let index = -1;
-
   for (let i = 0; i < array.length; i++) {
     if (array[i] === target) {
-      index = i;
+      return i;
     }
   }
-  return index;
+  return -1;
 }
 
 /**
@@ -32,8 +30,21 @@ function linearSearch(array, target) {
  */
 
 function binarySearch(array, target) {
-  let arrayLength = array.length / 2;
-  console.log(arrayLength);
+  let mid = Math.floor(array.length / 2);
+  let index = -1;
+
+  for (let i = 0; i < mid; i++) {
+    if (array[i] === target) {
+      return (index = i);
+    }
+
+    for (let j = array.length; j >= mid; j--) {
+      if (array[j] === target) {
+        return (index = j);
+      }
+    }
+    return index;
+  }
 }
 
 module.exports = {

From f730a4746356ffe0e1815ab777e3e717145db4b1 Mon Sep 17 00:00:00 2001
From: yko-git <yko.iwata@gmail.com>
Date: Tue, 12 Mar 2024 16:14:18 +0900
Subject: [PATCH 3/4] fix 002_search binarySearch

---
 004_algorithm/002_search.js | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/004_algorithm/002_search.js b/004_algorithm/002_search.js
index 68863d0..a54c533 100644
--- a/004_algorithm/002_search.js
+++ b/004_algorithm/002_search.js
@@ -30,21 +30,29 @@ function linearSearch(array, target) {
  */
 
 function binarySearch(array, target) {
-  let mid = Math.floor(array.length / 2);
-  let index = -1;
+  // 配列の位置を設定
+  let low = 0; //左端
+  let high = array.length - 1; //右端
 
-  for (let i = 0; i < mid; i++) {
-    if (array[i] === target) {
-      return (index = i);
-    }
+  //左端が右端以下の間（1つの要素に絞られるまで）は処理を続ける
+  while (low <= high) {
+    mid = low + high; // 真ん中の位置
+    guess = array[mid]; // 真ん中の要素
 
-    for (let j = array.length; j >= mid; j--) {
-      if (array[j] === target) {
-        return (index = j);
-      }
+    //真ん中の要素がtargetと合致したら
+    if (guess == target) {
+      //位置を返す
+      return mid;
+
+      //真ん中の要素がtargetより大きかったら
+    } else if (guess > target) {
+      //右端の位置は要素の位置-1
+      high = mid - 1;
+    } else {
+      low = mid + 1;
     }
-    return index;
   }
+  return -1;
 }
 
 module.exports = {

From 1d070b8932b6a3c7b644ca2a6f4d9f61d87115a4 Mon Sep 17 00:00:00 2001
From: yko-git <yko.iwata@gmail.com>
Date: Wed, 13 Mar 2024 14:55:21 +0900
Subject: [PATCH 4/4] fix 002_search binarySearch

---
 004_algorithm/002_search.js | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/004_algorithm/002_search.js b/004_algorithm/002_search.js
index a54c533..5e73518 100644
--- a/004_algorithm/002_search.js
+++ b/004_algorithm/002_search.js
@@ -31,18 +31,20 @@ function linearSearch(array, target) {
 
 function binarySearch(array, target) {
   // 配列の位置を設定
+  let index = -1;
   let low = 0; //左端
   let high = array.length - 1; //右端
 
   //左端が右端以下の間（1つの要素に絞られるまで）は処理を続ける
   while (low <= high) {
-    mid = low + high; // 真ん中の位置
-    guess = array[mid]; // 真ん中の要素
+    let mid = Math.floor((low + high) / 2); // 真ん中の位置
+    let guess = array[mid]; // 真ん中の要素
 
     //真ん中の要素がtargetと合致したら
     if (guess == target) {
       //位置を返す
-      return mid;
+      index = mid;
+      return index;
 
       //真ん中の要素がtargetより大きかったら
     } else if (guess > target) {
@@ -52,7 +54,7 @@ function binarySearch(array, target) {
       low = mid + 1;
     }
   }
-  return -1;
+  return index;
 }
 
 module.exports = {