HDU 5461 Largest Point （水）

#pragma warning(disable:4996)
#include <cmath>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const int N = 6000005;
typedef long long LL;
LL t
;
int n;
LL a, b;
vector<LL>vec;

int main(){
int T; scanf("%d", &T);
int kase = 1;
while (T--){
scanf("%d %lld %lld", &n, &a, &b);
vec.clear();
for (int i = 1; i <= n; i++){
int x;
scanf("%d", &x);
t[i] = (LL)x;
vec.push_back(t[i] * t[i]);
}
sort(t + 1, t + 1 + n);
sort(vec.begin(), vec.end());
LL ans = 0;

if (a > 0 && b > 0){
if (vec[vec.size() - 1] == t
* t
) {
ans = vec[vec.size() - 2] * a + b*t
;
}
else{
ans = vec[vec.size() - 1] * a + b*t
;
}
ans = max(ans, a*t
* t
+ b*t[n - 1]);
}
else if (a > 0 && b < 0) {
if (vec[vec.size() - 1] == t[1] * t[1]) {
ans = vec[vec.size() - 2] * a + b*t[1];
}
else{
ans = vec[vec.size() - 1] * a + b*t[1];
}
ans = max(ans, a*t[1] * t[1] + b*t[2]);
}
else if (a<0 && b>0) {
if (vec[0] == t
* t
){
ans = vec[1] * a + b*t
;
}
else{
ans = vec[0] * a + b*t
;
}
ans = max(ans, a*t
* t
+ b*t[n - 1]);
}
else if (a < 0 && b < 0){
if (vec[0] == t[1] * t[1]){
ans = vec[1] * a + b*t[1];
}
else{
ans = vec[0] * a + b*t[1];
}
ans = max(ans, a*t[1] * t[1] + b*t[2]);
}
else if (a == 0) {
if (b >= 0)ans = b*t
;
else ans = b*t[1];
}
else{
if (a > 0)ans = vec[vec.size() - 1] * a;
else ans = vec[0] * a;
}
printf("Case #%d: %lld\n", kase++, ans);
}
return 0;
}