codeforce 738 C Road to Cinema 選車 (二分)

　題意：你將從0點開車到s點，路上有一些加油站，加油時間忽略不計。你有兩種開車選擇，一種是每km走1min，花費2L油，另一種是每km走2min，花費1L油。你有n種汽車可以選擇，給出它們的油箱容量（剛開始滿的）和價格，能否選擇一輛價格最低的車，能在時間t內跑完全程。如果不能輸出-1

解題：直接二分油量，最低的油量需要多少....  再進行選車， 速度選擇上面稍加思考就能出。

Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's introduce a coordinate system so that the car rental service is at the point 0, and the cinema is at the point s.

There are k gas stations along the road, and at each of them you can fill a car with any amount of fuel for free! Consider that this operation doesn't take any time, i.e. is carried out instantly.

There are n cars in the rental service, i-th of them is characterized with two integers ci and vi — the price of this car rent and the capacity of its fuel tank in liters. It's not allowed to fuel a car with more fuel than its tank capacity vi. All cars are completely fueled at the car rental service.

Each of the cars can be driven in one of two speed modes: normal or accelerated. In the normal mode a car covers 1 kilometer in 2 minutes, and consumes 1 liter of fuel. In the accelerated mode a car covers 1 kilometer in 1 minutes, but consumes 2 liters of fuel. The driving mode can be changed at any moment and any number of times.

Your task is to choose a car with minimum price such that Vasya can reach the cinema before the show starts, i.e. not later than in t minutes. Assume that all cars are completely fueled initially. Input

The first line contains four positive integers n, k, s and t (1 ≤ n ≤ 2·105, 1 ≤ k ≤ 2·105, 2 ≤ s ≤ 109, 1 ≤ t ≤ 2·109) — the number of cars at the car rental service, the number of gas stations along the road, the length of the road and the time in which the film starts.

Each of the next n lines contains two positive integers ci and vi (1 ≤ ci, vi ≤ 109) — the price of the i-th car and its fuel tank capacity.

The next line contains k distinct integers g1, g2, ..., gk (1 ≤ gi ≤ s - 1) — the positions of the gas stations on the road in arbitrary order. Output

Print the minimum rent price of an appropriate car, i.e. such car that Vasya will be able to reach the cinema before the film starts (not later than in t minutes). If there is no appropriate car, print -1. Example Input

3 1 8 1010 85 711 93

Output

10

Input

2 2 10 1810 420 65 3

Output

20

Note

In the first sample, Vasya can reach the cinema in time using the first or the third cars, but it would be cheaper to choose the first one. Its price is equal to 10, and the capacity of its fuel tank is 8. Then Vasya can drive to the first gas station in the accelerated mode in 3 minutes, spending 6 liters of fuel. After that he can full the tank and cover 2 kilometers in the normal mode in 4 minutes, spending 2 liters of fuel. Finally, he drives in the accelerated mode covering the remaining 3 kilometers in 3 minutes and spending 6 liters of fuel.

#include<bits/stdc++.h>using namespace std;const int N = 2e5 + 100;const int inf = 0x3f3f3f3f;struct node{    int c,v;} a[N];int b[N],c[N];int t,k,s;int work1(int v){    int i,j,sum;    sum=0;    for(i=0; i<=k; i++)    {        sum+=c[i]*2-min(v-c[i],c[i]);    }    return sum;}int work(int l,int r){    int mid,num;    while(l<=r)    {        mid=(l+r)>>1;        num=work1(mid);        if(num<=t) r=mid-1;        else l=mid+1;    }    return l;}int main(){    int i,j,v,l,r,ans,n,tmp;    scanf("%d%d%d%d",&n,&k,&s,&t);    for(i=1; i<=n; i++) scanf("%d%d",&a[i].c,&a[i].v);    for(i=0; i<k; i++) scanf("%d",&b[i]);    sort(b,b+k);    c[0]=b[0];    for(i=1; i<k; i++) c[i]=b[i]-b[i-1];    c[k]=s-b[k-1];    l=0,r=0;    for(i=0; i<=k; i++) r+=c[i]*2,l=max(l,c[i]);    v=work(l,r);    ans=inf;    for(i=1; i<=n; i++)    {        if(a[i].v>=v) ans=min(ans,a[i].c);    }    if(ans==inf || work1(v)>t ) ans=-1;    printf("%d\n",ans);    return 0;}