SP348 EXPEDI - Expedition

嘟嘟嘟

水贪心。

当经过一个加油站的时候，记下这个加油站能加的油，然后没油的时候从经过的加油站中选择加油最多的加。

 #include<cstdio>
 #include<iostream>
 #include<cmath>
 #include<algorithm>
 #include<cstring>
 #include<cstdlib>
 #include<cctype>
 #include<vector>
 #include<stack>
 #include<queue>
 using namespace std;
 #define enter puts("")
 #define space putchar(' ')
 #define Mem(a, x) memset(a, x, sizeof(a))
 #define rg register
 typedef long long ll;
 typedef double db;
 const int INF = 0x3f3f3f3f;
 const db eps = 1e-;
 const int maxn = 1e4 + ;
 inline ll read()
 {
   ll ans = ;
   char ch = getchar(), last = ' ';
   while(!isdigit(ch)) {last = ch; ch = getchar();}
   while(isdigit(ch)) {ans = ans *  + ch - ''; ch = getchar();}
   if(last == '-') ans = -ans;
   return ans;
 }
 inline void write(ll x)
 {
   if(x < ) x = -x, putchar('-');
   if(x >= ) write(x / );
   putchar(x %  + '');
 }

 int n;
 struct Node
 {
   int d, val;
   bool operator < (const Node &oth)const
   {
     return d < oth.d;
   }
 }t[maxn];

 priority_queue<int> q;

 int main()
 {
   int T = read();
   while(T--)
     {
       while(!q.empty()) q.pop();
       n = read();
       for(int i = ; i <= n; ++i) t[i].d = read(), t[i].val = read();
       int dis = read(), p = read();
       for(int i = ; i <= n; ++i) t[i].d = dis - t[i].d;
       sort(t + , t + n + );
       int now = , ans = ;
       bool flg = ;
       int i = ;
       while(now < dis)
     {
       while(p - t[i].d + now >=  && i <= n)
         {
           p = p - t[i].d + now, now = t[i].d;
           q.push(t[i].val);
           i++;
         }
       if(now + p >= dis) break;
       if(q.empty()) {flg = ; break;}
       p += q.top(); q.pop(); ans++;
     }
       if(!flg) puts("-1");
       else write(ans), enter;
     }
   return ;
 }