P1901-发射站

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 4 #define _rep(i,a,b) for(int i = (a);i > b;i --)
 5 #define INF 0x3f3f3f3f
 6 #define pb push_back
 7 #define maxn 1005390
 8 typedef long long ll;
 9 typedef pair<int,int> P;//first 是最短距离，second 是顶点编号 
10 inline ll read()
11 {
12     ll ans = 0;
13     char ch = getchar(), last = ' ';
14     while(!isdigit(ch)) last = ch, ch = getchar();
15     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
16     if(last == '-') ans = -ans;
17     return ans;
18 }
19 inline void write(ll x)
20 {
21     if(x < 0) x = -x, putchar('-');
22     if(x >= 10) write(x / 10);
23     putchar(x % 10 + '0');
24 }
25 int N;
26 stack<ll> s;
27 ll in[maxn];
28 ll h[maxn],out[maxn];
29 int main()
30 {
31     N = read();
32     _for(i,1,N+1)
33     {
34         h[i] = read();
35         out[i] = read();
36     }
37     _for(i,1,N+1)
38     {
39         while(!s.empty() && h[s.top()] < h[i])
40         {
41             in[i] += out[s.top()];
42             s.pop();
43         }
44         if(!s.empty())
45             in[s.top()] += out[i];
46         s.push(i);
47     }
48     ll ans = 0;
49     _for(i,1,N+1)
50         ans = max(ans,in[i]);
51     write(ans);
52     return 0;
53 }