LeetCode Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product.

For example, given the array [2,3,-2,4],
the contiguous subarray [2,3] has the largest product = 6.

 

minLast[i] 表示以A[i]结尾的最小值，maxLast[i]表示以A[i]结尾的最大值。

minLast[i] = Math.min(A[i], Math.min(minLast[i - 1]*A[i], maxLast[i - 1]*A[i]));
maxLast[i] = Math.max(A[i], Math.max(maxLast[i - 1]*A[i], minLast[i - 1]*A[i]));

 

 1 public class Solution {
 2     public int maxProduct(int[] A) {
 3         int length = A.length;
 4         if (length == 0) {
 5             return 0;
 6         }
 7         int[] minLast = new int[length];
 8         int[] maxLast = new int[length];
 9         minLast[0] = A[0];
10         maxLast[0] = A[0];
11         int res = Integer.MIN_VALUE;
12         for (int i = 1; i <length ; i++) {
13             minLast[i] = Math.min(A[i], Math.min(minLast[i - 1]*A[i], maxLast[i - 1]*A[i]));
14             maxLast[i] = Math.max(A[i], Math.max(maxLast[i - 1]*A[i], minLast[i - 1]*A[i]));
15         }
16         for (int i : maxLast) {
17             if (i>res) res = i;
18         }
19         return res;
20     }
21 }

 

posted @ 2014-11-29 18:03  birdhack  阅读(125)  评论(0)  编辑  收藏  举报