Computes the sum of the largest subsequence of an array

Problem Description:

Computes the sum of the largest subsequence of a given array

Analysis:

There are three ways to do this:

1, Scan 3 times, you can calculate the sum of all sub-sequences, but the complexity of n^3.

2, Scan 2 times, calculate with any element start and, if greater than the current maximum value will pay it, the complexity of n^2.

3, scan again, calculate the value of any element start, if less than 0 clear zero, otherwise continue to add.

Code implementation:

package c02;/** *  @project: datastructureandalgorithmanalysis *  @filename:  maxsubsum *  @version: 0.10 *  @author: jimmy han *  @date:  21:35 2015/7/7 *  @comment:  calculates the back and, if negative, the starting point for each element, and then restarts the calculation  *  @result: 10  */public class maxsubsum {    public static void main (String [] args) {        int[] arr = {-1, 3, 2,  -3, -1, 4, 5};        system.out.println ( Maxsubsum (arr));     }    public static int maxsubsum (  int[] a) {        int maxsum = 0,  Thissum = 0;        for (int j = 0; j  < a.length; j++) {            thissum += a[j];             if (thissum > maxsum)                  maxSum =  Thissum;            else if (thisSum <  0)                  thissum = 0;        }         return maxsum;    }}

Computes the sum of the largest subsequence of an array