链接:点击打开链接
题意:求循环数组的最大子序列和
代码:
#include <iostream>
using namespace std;
long long num[100005];
int main()
{
long long n,i,sum1,sum2,summ,maxx,maxx1,maxx2;
while(cin>>n)
{
sum1=sum2=summ=maxx1=maxx2=0;
for(i=1;i<=n;i++)
{
cin>>num[i];
sum1+=num[i];
if(sum1<0)
sum1=0;
else if(sum1>maxx1)
maxx1=sum1;
summ+=num[i];
sum2-=num[i];
if(sum2<0)
sum2=0;
else if(sum2>maxx2)
maxx2=sum2; //同时求出最大子序列和和最小子序列和
}
//cout<<maxx1<<" "<<summ<<" "<<maxx2<<endl;
maxx=max(maxx1,summ+maxx2);
cout<<maxx<<endl;
}
return 0;
}