题意

ZR#317.【18 提高 2】A(计算几何 二分)-LMLPHP

ZR#317.【18 提高 2】A(计算几何 二分)-LMLPHP

Sol

非常好的一道题,幸亏这场比赛我没打,不然我估计要死在这个题上qwq

到不是说有多难,关键是细节太多了,我和wcz口胡了一下我的思路,然后他写了一晚上没调出来qwq

解法挺套路的,先提出一个$x$

然后维护一堆直线对应的上凸壳

在凸壳上二分即可。

由于这题的$x$很小,直接处理出答案就行了

/*

*/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<map>
#include<vector>
#include<set>
#include<queue>
#include<cmath>
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/hash_policy.hpp>
#define Pair pair<int, int>
#define MP(x, y) make_pair(x, y)
#define fi first
#define se second
#define int long long
#define LL long long
#define ull unsigned long long
#define rg register
#define pt(x) printf("%d ", x);
//#define getchar() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1<<22, stdin), p1 == p2) ? EOF : *p1++)
//char buf[(1 << 22)], *p1 = buf, *p2 = buf;
//char obuf[1<<24], *O = obuf;
//void print(int x) {if(x > 9) print(x / 10); *O++ = x % 10 + '0';}
//#define OS *O++ = ' ';
using namespace std;
//using namespace __gnu_pbds;
const int MAXN = 1e6 + , INF = 1e9 + , mod = 1e9 + , BB = ;
const double eps = 1e-;
inline int read() {
char c = getchar(); int x = , f = ;
while(c < '' || c > '') {if(c == '-') f = -; c = getchar();}
while(c >= '' && c <= '') x = x * + c - '', c = getchar();
return x * f;
}
int N;
struct Node {
double a, b;
bool operator < (const Node &rhs) const {
return a == rhs.a ? b < rhs.b : a < rhs.a;
}
}P[MAXN], s1[MAXN], s2[MAXN];
int t1 = , t2 = , ans[MAXN];
double cross(Node x, Node y) {
// printf("%lf\n", 1.0 * (y.b - x.b) / (x.a - x.b));
return 1.0 * (y.b - x.b) / (x.a - y.a);
}
void Get() {
sort(P + , P + N + );
s1[++t1] = P[];
for(int i = ; i <= N; i++) {
if(t1 && P[i].a == s1[t1].a) t1--;
while(t1 > && cross(P[i], s1[t1]) <= cross(s1[t1], s1[t1 - ])) t1--;
s1[++t1] = P[i];
}
for(int i = ; i <= N; i++) P[i].b = -P[i].b;
sort(P + , P + N + );
s2[++t2] = P[];
for(int i = ; i <= N; i++) {
if(t1 && P[i].a == s2[t2].a) t2--;
while(t2 > && cross(P[i], s2[t2]) <= cross(s2[t2], s2[t2 - ])) t2--;
s2[++t2] = P[i];
}
}
int Query(Node p, int x) {
return p.a * x * x + p.b * x;
}
void MakeAns() {
for(int i = , c = ; i <= BB; i++) {
//printf("%lf\n", cross(s1[c], s1[c + 1]));
while(c < t1 && cross(s1[c], s1[c + ]) <= (double)i) c++;
ans[i + BB] = Query(s1[c], i);
}
for(int i = , c = ; i <= BB; i++) {
while(c < t2 && cross(s2[c], s2[c + ]) <= (double)i) c++;
ans[BB - i] = Query(s2[c], i);
}
}
main() {
// freopen("a.in", "r", stdin);
N = read(); int Q = read();
for(int i = ; i <= N; i++) P[i].a = read(), P[i].b = read();
Get();
MakeAns();
while(Q--) {
int x = read();
printf("%lld\n", ans[x + BB]);
}
return ;
}
/*
2 2 1
1 1
2 1 1
*/
05-24 08:19