maximum product

leetcode/MaximumProductSubarray.cpp

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+// C++ program to find Maximum Product Subarray
+#include <bits/stdc++.h>
+using namespace std;
+
+/* Returns the product
+of max product subarray. */
+int maxSubarrayProduct(int arr[], int n)
+{
+    // max positive product
+    // ending at the current position
+    int max_ending_here = arr[0];
+
+    // min negative product ending
+    // at the current position
+    int min_ending_here = arr[0];
+
+    // Initialize overall max product
+    int max_so_far = arr[0];
+    /* Traverse through the array.
+    the maximum product subarray ending at an index
+    will be the maximum of the element itself,
+    the product of element and max product ending previously
+    and the min product ending previously. */
+    for (int i = 1; i < n; i++) {
+        int temp = max({ arr[i], arr[i] * max_ending_here,
+                         arr[i] * min_ending_here });
+        min_ending_here
+            = min({ arr[i], arr[i] * max_ending_here,
+                    arr[i] * min_ending_here });
+        max_ending_here = temp;
+        max_so_far = max(max_so_far, max_ending_here);
+    }
+    return max_so_far;
+}
+
+// Driver code
+int main()
+{
+    int arr[] = { 1, -2, -3, 0, 7, -8, -2 };
+    int n = sizeof(arr) / sizeof(arr[0]);
+    cout << "Maximum Sub array product is "
+         << maxSubarrayProduct(arr, n);
+    return 0;
+}
+