B - Make It Increasing

https://codeforces.com/contest/1675/submission/155955441

Codeforces/1675/B/B.cpp

@@ -0,0 +1,47 @@
+#include <cmath>
+#include <iostream>
+#include <limits>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 35;
+
+int t, n, a[N], ans;
+bool flag;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> t;
+
+    while (t--) {
+        ans = 0;
+        flag = false;
+
+        cin >> n;
+
+        for (int i = 1; i <= n; i++) {
+            cin >> a[i];
+        }
+
+        a[n + 1] = std::numeric_limits<int>::max();
+
+        for (int i = n; i; i--) {
+            while (a[i] >= a[i + 1]) {
+                a[i] = std::floor(1.0 * a[i] / 2);
+                ans++;
+            }
+
+            if (a[i] == 0 && i != 1) {
+                flag = true;
+                break;
+            }
+        }
+
+        cout << (flag ? -1 : ans) << endl;
+    }
+
+    return 0;
+}