P1115 Code

/*火车头*/
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<string>
#include<deque>
#include<exception>
#include<fstream>
#include<functional>
#include<limits>
#include<list>
#include<map>
#include<iomanip>
#include<ios>
#include<sstream>
#include<stack>
#include<bitset>
#include<cctype>
#include<stdexcept>
#include<streambuf>
#include<utility>
#include<vector>
#include<iosfwd>
#include<cerrno>
#include<clocale>
#include<complex>
#include<cstdlib>
#include<ctime>
#include<istream>
#include<ostream>
#include<queue>
#include<set>
#include<cwchar>
#include<cwctype>
#include<complex.h>
#include<fenv.h>
#include<inttypes.h>
#include<stdbool.h>
#include<stdint.h>
#include<tgmath.h>
#include<stdlib.h>
#include<time.h>
#define gc getchar();
#define maxn 200010
using namespace std;
inline int read()
{
    int x=0; 
    bool sgn=0;
    char s=gc
    while(!isdigit(s))sgn|=s=='-',s=gc
    while(isdigit(s))x=(x<<1)+(x<<3)+(s-'0'),s=gc
    return sgn?-x:x;
}
int n,ans=-0x7fffffff;
int f[maxn],a[maxn];
int main()
{
    cin>>n;
    for (int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    for (int i=1;i<=n;i++)
    {
        f[i]=max(f[i-1],0)+a[i];
        ans=max(ans,f[i]);
    }
    printf("%d",ans);
    return 0;
}