B. Marvolo Gaunt’s Ringtime limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
Professor Dumbledore is helping Harry destroy the Horcruxes. He went to Gaunt Shack as he suspected a Horcrux to be present there. He saw Marvolo Gaunt’s Ring and identified it as a Horcrux. Although he destroyed it, he is still affected by its curse. Professor Snape is helping Dumbledore remove the curse. For this, he wants to give Dumbledore exactly x drops of the potion he made.
Value of x is calculated as maximum of p·ai + q·aj + r·ak for given p, q, r and array a1, a2, … an such that 1 ≤ i ≤ j ≤ k ≤ n. Help Snape find the value of x. Do note that the value of x may be negative.
Input
First line of input contains 4 integers n, p, q, r ( - 109 ≤ p, q, r ≤ 109, 1 ≤ n ≤ 105).
Next line of input contains n space separated integers a1, a2, … an ( - 109 ≤ ai ≤ 109).
Output
Output a single integer the maximum value of p·ai + q·aj + r·ak that can be obtained provided 1 ≤ i ≤ j ≤ k ≤ n.
ExamplesInput
5 1 2 3
1 2 3 4 5
Output
30
Input
5 1 2 -3
-1 -2 -3 -4 -5
Output
12
Note
In the first sample case, we can take i = j = k = 5, thus making the answer as 1·5 + 2·5 + 3·5 = 30.
In second sample case, selecting i = j = 1 and k = 5 gives the answer 12.
这题题意是给定p，q，r，要求从数组中选择 i，j，k （i<=j<=k)
使得 p*i + q*j + r*k 最大，就是道暴力模拟水题，我竟然没有想到T T，直接掉了80分。。。
哇，我真的是个智障。
附ac代码：
1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 #include <cmath>
5 #include <algorithm>
6 #include <map>
7 #define ll long long
8 using namespace std;
9 const ll inf = -4*1e18-5;
10
11 int main() {
12 int n;
13 scanf("%d",&n);
14 ll p,q,r;
15 scanf("%lld%lld%lld",&p,&q,&r);
16 ll u,m1,m2,m3;
17 // printf("%lld ",inf);
18 m1 = m2 = m3 =inf;
19 while(n--) {
20 scanf("%lld",&u);
21 m1 = max(m1,u*p);
22 m2 = max(m2,u*q + m1);
23 m3 = max(m3,u*r + m2);
24 }
25 printf("%lld\n",m3);
26 return 0;
27 }
