SGU 199 Beautiful People 二维最长递增子序列

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<vector>
 6 using namespace std;
 7 
 8 const int maxn = 1e5 + 10;
 9 
10 struct Node {
11     int x, y,id;
12     bool operator < (const Node& tmp) const {
13         return x < tmp.x||x==tmp.x&&y>tmp.y;
14     }
15 }arr[maxn];
16 
17 int n,maxlen;
18 int pre[maxn],dp[maxn],yy[maxn];
19 
20 void init() {
21     memset(pre, -1, sizeof(pre));
22     maxlen = 0;
23 }
24 
25 int main() {
26     while (scanf("%d", &n) == 1 && n) {
27         init();
28         for (int i = 0; i < n; i++) {
29             scanf("%d%d", &arr[i].x, &arr[i].y);
30             arr[i].id = i + 1;
31         }
32         sort(arr, arr + n);
33         dp[0] = 1; yy[++maxlen] = 0;
34         for (int i = 1; i < n; i++) {
35             int low = 1, hig = maxlen+1;
36             if (arr[i].y <= arr[yy[low]].y) {
37                 yy[low] = i;
38                 continue;
39             }
40             while (low + 1 < hig) {
41                 int mid = low + (hig - low) / 2;
42                 if (arr[yy[mid]].y < arr[i].y) low = mid;
43                 else hig = mid;
44             }
45             pre[i] = yy[low];
46             int len = low + 1;
47             if (len > maxlen) {
48                 yy[++maxlen] = i;
49             }
50             else {
51                 if (arr[i].y < arr[yy[len]].y) yy[len] = i;
52             }
53         }
54         vector<int> ans;
55         int p = yy[maxlen];
56         while (p != -1) {
57             ans.push_back(p);
58             p = pre[p];
59         }
60         printf("%d\n", ans.size());
61         for (int i = 0; i < ans.size() - 1; i++) printf("%d ", arr[ans[i]].id);
62         printf("%d\n", arr[ans[ans.size() - 1]].id);
63     }
64     return 0;
65 }