Caravan Robbers CF Gym

https://cn.vjudge.net/problem/Gym-100134C
http://codeforces.com/gym/100134/attachments

答案就是最小的min(bi-aj)/(i-j+1)
用斜率优化
维护一个上凸壳在上面三分答案

插入的时候插入原点
算答案的时候再+1 当做当前点往右偏移了一个位置

#include <iostream>
#include <algorithm>
#include <sstream>
#include <string>
#include <queue>
#include <cstdio>
#include <map>
#include <set>
#include <utility>
#include <stack>
#include <cstring>
#include <cmath>
#include <vector>
#include <ctime>
#include <bitset>
#include <assert.h>
using namespace std;
#define pb push_back
#define sd(n) scanf("%d",&n)
#define sdd(n,m) scanf("%d%d",&n,&m)
#define sddd(n,m,k) scanf("%d%d%d",&n,&m,&k)
#define sld(n) scanf("%lld",&n)
#define sldd(n,m) scanf("%lld%lld",&n,&m)
#define slddd(n,m,k) scanf("%lld%lld%lld",&n,&m,&k)
#define sf(n) scanf("%lf",&n)
#define sff(n,m) scanf("%lf%lf",&n,&m)
#define sfff(n,m,k) scanf("%lf%lf%lf",&n,&m,&k)
#define ss(str) scanf("%s",str)
#define ansn() printf("%d\n",ans)
#define lansn() printf("%lld\n",ans)
#define r0(i,n) for(int i=0;i<(n);++i)
#define r1(i,e) for(int i=1;i<=e;++i)
#define rn(i,e) for(int i=e;i>=1;--i)
#define mst(abc,bca) memset(abc,bca,sizeof abc)
#define lowbit(a) (a&(-a))
#define all(a) a.begin(),a.end()
#define pii pair<int,int>
#define pll pair<long long,long long>
#define mp(aa,bb) make_pair(aa,bb)
#define lrt rt<<1
#define rrt rt<<1|1
#define X first
#define Y second
#define PI (acos(-1.0))
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
//const ll mod = 1000000007;
const double eps=1e-12;
const int inf=0x3f3f3f3f;
//const ll infl = 100000000000000000;//1e17
const int maxn=  2e6+20;
const int maxm = 2e3+20;
//muv[i]=(p-(p/i))*muv[p%i]%p;
int in(int &ret) {char c;int sgn ;if(c=getchar(),c==EOF)return -1;while(c!='-'&&(c<'0'||c>'9'))c=getchar();sgn = (c=='-')?-1:1;ret = (c=='-')?0:(c-'0');while(c=getchar(),c>='0'&&c<='9')ret = ret*10+(c-'0');ret *=sgn;return 1;
}
pii a[maxn];
int p,q;
int qq[maxn];
void update(int p2,int q2) { //p/q > p2/q2,if(1LL*p*q2>1LL*p2*q)p = p2,q = q2;
}
int main() {
#ifdef LOCALfreopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
#endif // LOCAL
//    freopen("caravan.in","r",stdin);
//    freopen("caravan.out","w",stdout);int n;sd(n);r1(i,n)sdd(a[i].X,a[i].Y);sort(a+1,a+1+n);p = 1e9,q = 1;for(int i=1; i<=n; ++i) {int j = i;while(j<n&&a[j+1].X<a[j].Y)++j;int sz = 0;for(int k=i; k<=j; ++k) {int t = a[k].X;while(sz>=2) {int e = qq[sz-1],w = qq[sz-2];
//                if((t-a[q].X)/(k-q+1)<(a[e].X-a[w].X)/(e-w+1))if(1LL*(t-a[e].X)*(e-w)>=1LL*(a[e].X-a[w].X)*(k-e))--sz;else break;}qq[sz++] = k;int l = 1,r = sz;int b = a[k].Y;while(l<r-1) {int mid = (l+r)/2 ;int mmid = (mid+r)/2 ;int x = qq[mid-1];int y = qq[mmid-1];
//                if((b-a[x].Y)/(k-x+1)<(b-a[y].Y)/(k-y+1))r = mmid;if(1LL*(b-a[x].X)*(k-y+1)<1LL*(b-a[y].X)*(k-x+1))r = mmid;else l = mid;}int x = qq[l-1],y = qq[r-1];int p;if(1LL*(b-a[x].X)*(k-y+1)<1LL*(b-a[y].X)*(k-x+1))p = x;else p = y;update(b-a[p].X,k-p+1);}i = j;}int gcd = __gcd(p,q);p/=gcd;q/=gcd;printf("%d/%d\n",p,q);return 0;
}

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