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.
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 a single integer the maximum value of p·ai + q·aj + r·ak that can be obtained provided 1 ≤ i ≤ j ≤ k ≤ n.
5 1 2 3
1 2 3 4 5
30
5 1 2 -3
-1 -2 -3 -4 -5
12
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 ",m3); 26 return 0; 27 }