From ae267fed2313d43edd1a37d9651483d65df97053 Mon Sep 17 00:00:00 2001
From: Matej Focko <mfocko@redhat.com>
Date: Sat, 10 Jun 2023 21:58:32 +0200
Subject: [PATCH] =?UTF-8?q?problems(cpp):=20add=20=E2=80=9C1802.=20Maximum?=
 =?UTF-8?q?=20Value=20at=20a=20Given=20Index=20in=20a=20Bounded=20Array?=
 =?UTF-8?q?=E2=80=9D?=
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Signed-off-by: Matej Focko <mfocko@redhat.com>
---
 ...ue-at-a-given-index-in-a-bounded-array.cpp | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 problems/cpp/maximum-value-at-a-given-index-in-a-bounded-array.cpp

diff --git a/problems/cpp/maximum-value-at-a-given-index-in-a-bounded-array.cpp b/problems/cpp/maximum-value-at-a-given-index-in-a-bounded-array.cpp
new file mode 100644
index 0000000..f2c4cda
--- /dev/null
+++ b/problems/cpp/maximum-value-at-a-given-index-in-a-bounded-array.cpp
@@ -0,0 +1,54 @@
+#include <cassert>
+
+namespace {
+long sum(long index, long value, long n)
+{
+    long count = 0;
+
+    if (value > index) {
+        count += (2 * value - index) * (index + 1) / 2;
+    } else {
+        count += (value + 1) * value / 2 + index - value + 1;
+    }
+
+    if (value >= n - index) {
+        count += (2 * value - n + 1 + index) * (n - index) / 2;
+    } else {
+        count += (value + 1) * value / 2 + n - index - value;
+    }
+
+    return count - value;
+}
+}
+
+class Solution {
+public:
+    int maxValue(int n, int index, int maxSum)
+    {
+        int left = 1, right = maxSum;
+
+        while (left < right) {
+            int mid = (left + right + 1) / 2;
+            if (sum(index, mid, n) <= maxSum) {
+                left = mid;
+            } else {
+                right = mid - 1;
+            }
+        }
+
+        return left;
+    }
+};
+
+int main()
+{
+    Solution s;
+
+    assert(s.maxValue(4, 2, 6) == 2);
+    assert(s.maxValue(6, 1, 10) == 3);
+
+    // regression
+    assert(s.maxValue(6, 2, 931384943) == 155230825);
+
+    return 0;
+}