First Bad Version: binary search. mid = (l>>1)+(r>>1)+(l&r&1);

Author: DeanChensj

Easy/278_First-Bad-Version.cpp

@@ -0,0 +1,12 @@
+#include "../Header.h"
+
+using namespace std;
+int firstBadVersion(int n) {
+    int l = 1, r = n, mid;
+    while (l < r) {
+        mid = (l >> 1) + (r >> 1) + (l & 1 & r);
+        if (isBadVersion(mid)) r = mid;
+        else l = mid + 1;
+    }
+    return r;
+}