- 给定n个整数(可能为负数)组成的序列a[1],a[2],a[3],…,a[n],求该序列如a[i]+a[i+1]+…+a[j]的子段和的最大值。当所给的整数均为负数时定义子段和为0,依此定义,所求的最优值为: Max{0,a[i]+a[i+1]+…+a[j]},1<=i<=j<=n
例如,当(a[1],a[2],a[3],a[4],a[5],a[6])=(-2,11,-4,13,-5,-2)时,最大子段和为20。
二.源代码
import java.util.Scanner;
public class ziduanhe {
public static void main(String[] args) {
int[] a=new int[100];
int i=0;
int count=0;
Scanner sc = new Scanner(System.in);
count=sc.nextInt();
for(i=0; i<count; i++)
{
a[i]=sc.nextInt();
}
System.out.println(max(count,a));
}
public static int max(int count,int [] a) {
int[] b=new int[100];
int max,i;
b[0]=a[0];
max=b[0];
for(i=1; i<count; i++)
{
if(b[i-1]>0)
{
b[i]=b[i-1]+a[i];
}
else
{
b[i]=a[i];
}
if(b[i]>max)
{
max=b[i];
}
}
if(max<0)
max=0;
return max;
}
}
三.判断/条件覆盖流程图
四.测试样例
import static org.junit.Assert.*;
import org.junit.Test;
import my1.ziduanhe;
public class ziduanheTest {
@Test
public void Testmax1() {
new ziduanhe();
assertEquals(0,ziduanhe.max(0,new int [] {0}));
}
@Test
public void Testmax2() {
new ziduanhe();
assertEquals(0,ziduanhe.max(6,new int [] {-1,-2,-3,-4,-5,-6}));
}
@Test
public void Testmax3() {
new ziduanhe();
assertEquals(20,ziduanhe.max(6,new int [] {-2,11,-4,13,-5,-2}));
}
}