Create maximum-number-of-ways-to-partition-an-array.cpp

Author: kamyu104

C++/maximum-number-of-ways-to-partition-an-array.cpp

@@ -0,0 +1,24 @@
+// Time:  O(n)
+// Space: O(n)
+
+class Solution {
+public:
+    int waysToPartition(vector<int>& nums, int k) {
+        const int64_t total = accumulate(begin(nums), end(nums), 0LL);
+        unordered_map<int64_t, int> right;
+        for (int64_t i = 0, prefix = 0; i < size(nums) - 1; ++i) {
+            prefix += nums[i];
+            ++right[prefix - (total - prefix)];
+        }
+        int64_t result = right[0];
+        unordered_map<int64_t, int> left;
+        int64_t prefix = 0;
+        for (const auto& x : nums) {
+            result = max(result, static_cast<int64_t>(left[k - x]) + right[-(k - x)]);
+            prefix += x;
+            --right[prefix - (total - prefix)];
+            ++left[prefix - (total - prefix)];
+        }
+        return result;
+    }
+};