toj 4071 最长不下降子序列nlogn解法

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <cstdio>
 4 using namespace std;
 5 
 6 const int N = 100000;
 7 int s[N];
 8 int top;
 9 
10 struct Node 
11 {
12     int x, y;
13 } node[N];
14 
15 bool cmp( Node a, Node b )
16 {
17     if ( a.x != b.x ) return a.x < b.x;
18     return a.y < b.y;
19 }
20 
21 int main ()
22 {
23     int t;
24     scanf("%d", &t);
25     while ( t-- )
26     {
27         int n;
28         scanf("%d", &n);
29         for ( int i = 0; i < n; i++ )
30         {
31             scanf("%d%d", &node[i].x, &node[i].y);
32         }
33         sort( node, node + n, cmp );
34         top = 0;
35         s[top++] = node[0].y;
36         for ( int i = 1; i < n; i++ )
37         {
38             if ( node[i].y >= s[top - 1] )
39             {
40                 s[top++] = node[i].y;
41             }
42             else
43             {
44                 int tmp = upper_bound( s, s + top, node[i].y ) - s;
45                 s[tmp] = node[i].y;                
46             }
47         }
48         printf("%d\n", top);        
49     }
50     return 0;
51 }