Update 152-maximum-product-subarray.js

Author: everthis

152-maximum-product-subarray.js

@@ -1,3 +1,32 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+const maxProduct = function(nums) {
+    let A = nums
+    let r = A[0];
+
+    // imax/imin stores the max/min product of
+    // subarray that ends with the current number A[i]
+    for (let i = 1, imax = r, imin = r, n = A.length; i < n; i++) {
+        if (A[i] < 0) {
+          let tmp = imax
+          imax = imin
+          imin = tmp
+        };
+        // max/min product for the current number is either the current number itself
+        // or the max/min by the previous number times the current one
+        imax = Math.max(A[i], imax * A[i]);
+        imin = Math.min(A[i], imin * A[i]);
+
+        // the newly computed max value is a candidate for our global result
+        r = Math.max(r, imax);
+    }
+    return r;
+};
+
+// another
+
 /**
  * @param {number[]} nums
  * @return {number}