P1233-木棍加工

 1 #pragma GCC optimize("Ofast")
 2 #include <bits/stdc++.h>
 3 #define maxn 13003
 4 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 5 typedef long long ll;
 6 using namespace std;
 7 
 8 inline ll read()
 9 {
10     ll ans = 0;
11     char ch = getchar(), last = ' ';
12     while(!isdigit(ch)) last = ch, ch = getchar();
13     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
14     if(last == '-') ans = -ans;
15     return ans;
16 }
17 inline void write(ll x)
18 {
19     if(x < 0) x = -x, putchar('-');
20     if(x >= 10) write(x / 10);
21     putchar(x % 10 + '0');
22 }
23 struct wood
24 {
25     int W;
26     int L;
27 };
28 int n;
29 wood in[5003];
30 int dp[5003];
31 int dpend = 1;
32 bool cmp(wood a,wood b)
33 {
34     if(a.L == b.L)
35         return a.W > b.W;
36     return a.L > b.L;
37 }
38 
39 int main()
40 {
41     n = read();
42     _for(i,1,n+1)
43     {
44         in[i].L = read();
45         in[i].W = read();
46     }
47     sort(in+1,in+n+1,cmp);
48 
49     dp[dpend] = in[1].W;
50     _for(i,2,n+1)
51     {
52         if(in[i].W > dp[dpend])
53             dp[++dpend] = in[i].W;
54         else
55         {
56             int t = lower_bound(dp+1,dp+dpend+1,in[i].W)-dp;
57             dp[t] = in[i].W;
58         }
59     }
60     write(dpend);
61     return 0;
62 }