中国大学MOOC-陈越、何钦铭-数据结构-2020春---实现代码

求最大子列和问题实现代码4

Java实现

 1 import java.util.Scanner;
 2 
 3 public class main{
 4     public static void main(String[] args) {
 5         Scanner scanner = new Scanner(System.in);
 6         int N=0;
 7         N = scanner.nextInt()+1;
 8        // N=N+1;
 9         int []arr=new int[N];
10 
11         int i=0;
12         for(;i<N;i++){
13             arr[i]=i;
14         }
15         long startTime = System.nanoTime();//开始计时
16         int Max=MaxSubseqSum4(arr,N);
17         long estimatedTime = System.nanoTime()-startTime;//结束计时，求的总时长
18         System.out.println(Max);
19         System.out.println(estimatedTime+"纳秒");
20     }
21 
22     private static int MaxSubseqSum4(int[] arr, int n) {
23         int ThisSum,MaxSum;
24         ThisSum=MaxSum=0;
25         int i = 0;
26         for(;i<n;i++){
27             ThisSum = arr[i]+ThisSum;/*向右累加*/
28             if(ThisSum >= MaxSum)/*发现更大和则更新当前结果*/
29                 MaxSum = ThisSum;/*如果当前子列和为负*/
30             else
31                 ThisSum=0;/*则不可能使后面的部分和增大，抛弃之*/
32 
33         }
34         return MaxSum;
35     }
36 
37 }

import java.util.Scanner;

public class main{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int N=0;
        N = scanner.nextInt()+1;
       // N=N+1;
int []arr=new int[N];

        int i=0;
        for(;i<N;i++){
            arr[i]=i;
        }
        long startTime = System.nanoTime();//开始计时
int Max=MaxSubseqSum4(arr,N);
        long estimatedTime = System.nanoTime()-startTime;//结束计时，求的总时长
System.out.println(Max);
        System.out.println(estimatedTime+"纳秒");
    }

    private static int MaxSubseqSum4(int[] arr, int n) {
        int ThisSum,MaxSum;
        ThisSum=MaxSum=0;
        int i = 0;
        for(;i<n;i++){
            ThisSum = arr[i]+ThisSum;/*向右累加*/
if(ThisSum >= MaxSum)/*发现更大和则更新当前结果*/
MaxSum = ThisSum;/*如果当前子列和为负*/
else
ThisSum=0;/*则不可能使后面的部分和增大，抛弃之*/

}
        return MaxSum;
    }

}