swust oj 585--倒金字塔(LIS最长不下降子序列)

 1 #include <iostream>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 struct node{
 6     int x, y;
 7     bool operator<(const node &tmp)const{
 8         if (x != tmp.x) 
 9             return x < tmp.x;
10         return y < tmp.y;
11     }
12 }tower[100005];
13 
14 int n, len, dp[100005];
15 
16 int binary_search(int key, int low, int high){
17     while (low < high){
18         int mid = (low + high) >> 1;
19         if (key >= dp[mid]) 
20             low = mid + 1;
21         else  high = mid;
22     }
23     return low;
24 }
25 
26 int main(){
27     int i, j;
28     while (cin >> n){
29         for (i = 0; i < n; i++) cin >> tower[i].x >> tower[i].y;
30         sort(tower, tower + n);
31         dp[1] = tower[0].y, len = 1;
32         for (i = 1; i < n; i++){
33             if (dp[len] <= tower[i].y)  j = ++len;
34             else
35                 j = binary_search(tower[i].y, 1, len + 1);
36             dp[j] = tower[i].y;
37         }
38         cout << len << endl;
39     }
40     return 0;
41 }