From 7468f361189f9a32fb7d02e033d7174a3c1ef182 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <dcariotti24@gmail.com>
Date: Sun, 19 Jul 2020 22:58:15 +0200
Subject: chore: binary search

---
 I_anno/Programmazione_2/algorithms/binarysearch.cc | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 I_anno/Programmazione_2/algorithms/binarysearch.cc

diff --git a/I_anno/Programmazione_2/algorithms/binarysearch.cc b/I_anno/Programmazione_2/algorithms/binarysearch.cc
new file mode 100644
index 0000000..c9b4cd7
--- /dev/null
+++ b/I_anno/Programmazione_2/algorithms/binarysearch.cc
@@ -0,0 +1,33 @@
+#include<iostream>
+
+using namespace std;
+
+bool bs(int a[], int i, int j, int x) {
+    if(j<i) return false;
+    int mid = i+(j-i)/2;
+    if(a[mid] == x)
+        return true;
+    if(a[mid] > x)
+        return bs(a, i, mid-1, x);
+    return bs(a, mid+1, j, x);
+}
+
+bool bs2(int a[], int i, int j, int x) {
+    while(i <= j) {
+        int mid = i+(j-i)/2;
+        if(a[mid] == x) return true;
+        if(a[mid] < x)
+            i = mid+1;
+        else
+            j = mid-1;
+    }
+    return false;
+}
+
+int main() {
+    int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    for(int i = 0; i < 12; ++i)
+        cout << i << ' '<<bs(a, 0, 9, i) << ' ' << bs2(a, 0, 9, i) << endl;
+    return 0;
+}
+
-- 
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