Luogu2858[USACO06FEB]奶牛零食Treats for the Cows （区间DP）

我是个傻逼，这么水的题都会T

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long

#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);

#else

#define D_e_Line ;
#define D_e(x)  ;
#define Pause() ;
#define FileOpen() ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

const int N = 2007;

int f[N][N], a[N];
int main(){
	//FileOpen();

	int n;
	io >> n;
	R(i,1,n){
		io >> a[i];
		f[i][i] = a[i] * n;
	}

	R(len,2,n){
		R(l,1,n){
			int r = l + len - 1;
			if(r > n) break; // what happend to my mind that I'm dare to write 'continue' !
			f[l][r] = Max(f[l][r - 1] + a[r] * (n - len + 1), f[l + 1][r] + a[l] * (n - len + 1)); // Shit, I put another for insideeeeeeeeeeeeeeee
		}
	}

	printf("%d\n", f[1][n]);

	return 0;
}