最大字段和问题
问题描述：
Given a sequence a[1],a[2],a[3]......a[n], your job is to calculate the max sum of a sub-sequence. For example, given (6,-1,5,4,-7), the max sum in this sequence is 6 + (-1) + 5 + 4 = 14.
输入：
The first line of the input contains an integer T(1<=T<=20) which means the number of test cases. Then T lines follow, each line starts with a number N(1<=N<=100000), then N integers followed(all the integers are between -1000 and 1000).
输出：
For each test case, you should output two lines. The first line is "Case #:", # means the number of the test case. The second line contains three integers, the Max Sum in the sequence, the start position of the sub-sequence, the end position of the sub-sequence. If there are more than one result, output the first one. Output a blank line between two cases.
#include<iostream>
using namespace std;
int main()
{
int cas;
cin>>cas;
int index=1;
while (index<=cas)
{
int n;
cin>>n;
int a[n];
int b[n];
int l[n];
int r[n];
for(int i=1;i<=n;i++)
cin>>a[i];
int sum=-1000010;
b[0]=0;
l[1]=1,r[1]=1;
int tmp=1;
for(int i=1;i<=n;i++)
{
if(b[i-1]>=0)
{
b[i]=b[i-1]+a[i];
r[i]=i;
l[i]=tmp;
}
else
{
b[i]=a[i];
r[i]=i;
l[i]=i;
tmp=i;
}
}
for(int i=1;i<=n;i++){
if(b[i]>sum){
sum=b[i];
tmp=i;
}
}
cout<<"Case "<<index<<":"<<endl;
cout<<sum<<" "<<l[tmp]<<" "<<r[tmp]<<endl;
if(index!=cas)
cout<<endl;
index++;
}
return 0;
}
posted on 2012-05-13 21:00
cc272301926 阅读(72)
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