RT，本人代码开 C++14 就 TLE，开 C++20 就 AC，最慢的点 $3.6s$，这是为啥呀。

代码：

#define orz GCC
#pragma orz optimize("Ofast,-falign-functions,-falign-jumps,-falign-labels,-falign-loops,-fcaller-saves,-fcrossjumping,-fcse-follow-jumps,-fdelete-null-pointer-checks,-fdevirtualize,-fexpensive-optimizations,-ffast-math,-fgcse,-fgcse-lm,-fhoist-adjacent-loads,-findirect-inlining,-finline,-fipa-sra,-fno-stack-protector,-foptimize-sibling-calls,-fpartial-inlining,-fpeephole2,-freorder-blocks,-freorder-functions,-frerun-cse-after-loop,-fsched-interblock,-fsched-spec,-fschedule-insns,-fschedule-insns2,-fstrict-aliasing,-fthread-jumps,-ftree-pre,-ftree-switch-conversion,-ftree-tail-merge,-ftree-vrp,-funroll-loops")
#pragma orz target("abm,avx,mmx,popcnt,sse,sse2,sse3,sse4,ssse3,tune=native")
#include<bits/stdc++.h>
using namespace std;
// #define DEBUG 1  // 调试开关
struct IO{//by Tx_Lcy
    #define MAXSIZE (1<<20)
    #define isdigit(x) (x>='0'&&x<='9')
    char buf[MAXSIZE],*p1,*p2;
    char pbuf[MAXSIZE],*pp;
    #if DEBUG
    #else
        IO():p1(buf),p2(buf),pp(pbuf){}
        ~IO(){fwrite(pbuf,1,pp-pbuf,stdout);}
    #endif
    inline char gc(){
        #if DEBUG
            return getchar();
        #endif
            if (p1==p2) p2=(p1=buf)+fread(buf,1,MAXSIZE,stdin);
            return p1==p2?' ':*p1++;
    }
    inline bool blank(char ch){return ch==' '||ch=='\n'||ch=='\r'||ch=='\t';}
    template <class T>
    inline void read(T &x){
        double tmp=1;bool sign=0;
        x=0;char ch=gc();
        for (;!isdigit(ch);ch=gc()) if (ch=='-') sign=1;
        for (; isdigit(ch);ch=gc()) x=x*10+(ch-'0');
        if (ch=='.')
        for (ch=gc();isdigit(ch);ch=gc()) tmp/=10.0,x+=tmp*(ch-'0');
        if (sign) x=-x;
    }
    inline void read(char *s){
        char ch = gc();
        for (;blank(ch);ch=gc());
        for (;!blank(ch);ch=gc()) *s++=ch;
        *s=0;
    }
    inline void read(char &c){for (c=gc();blank(c);c=gc());}
    inline void push(const char &c) {
        #if DEBUG
            putchar(c);
        #else
            if (pp-pbuf==MAXSIZE) fwrite(pbuf,1,MAXSIZE,stdout),pp=pbuf;
            *pp++=c;
        #endif
    }
    template <class T>
    inline void write(T x){
        if (x<0) x=-x,push('-');
        static T sta[35];T top=0;
        do{sta[top++]=x%10,x/=10;}while (x);
        while (top) push(sta[--top]+'0');
    }
    template <class T>
    inline void write(T x,char lastChar){write(x),push(lastChar);}
    template <class T>
    inline void writeln(T x){write(x);push('\n');}
}io;
int const N=1e5+10;
long long f[N];
signed main(){
	int n;io.read(n);
	for (register int i=1;i<=n;++i) f[i]=-1e18;
	for (register int i=1;i<=n;++i){
		long long x;io.read(x);
		for (register int j=i;j;--j) f[j]=max(f[j],f[j-1]+j*x);
	}
	io.write(max(*max_element(f+1,f+n+1),0ll));
	return 0;
}