poj2528---Mayor's posters

 1 #include <set>
 2 #include <map>
 3 #include <cmath>
 4 #include <ctime>
 5 #include <queue>
 6 #include <stack>
 7 #include <cctype>
 8 #include <cstdio>
 9 #include <string>
10 #include <vector>
11 #include <cstdlib>
12 #include <cstring>
13 #include <iostream>
14 #include <algorithm>
15 using namespace std;
16 typedef unsigned long long ull;
17 typedef long long ll;
18 const int inf = 0x3f3f3f3f;
19 const double eps = 1e-8;
20 const int maxn = 2e4+10;
21 int n,a[maxn*2],setv[maxn<<2];
22 void push_down(int pos)
23 {
24     if (~setv[pos])
25     {
26         setv[pos<<1] = setv[pos<<1|1] = setv[pos];
27         setv[pos] = -1;
28     }
29 }
30 void update(int l,int r,int pos,int ua,int ub,int v)
31 {
32     if (ua <= l && ub >= r)
33         setv[pos] = v;
34     else
35     {
36         push_down(pos);
37         int mid = (l + r) >> 1;
38         if (ua <= mid)
39             update(l,mid,pos<<1,ua,ub,v);
40         if (ub > mid)
41             update(mid+1,r,pos<<1|1,ua,ub,v);
42     }
43 }
44 int query(int l,int r,int pos,int ua,int ub)
45 {
46     if (~setv[pos])
47     {
48         return setv[pos] * (min(ub,r) - max(ua,l) + 1);
49     }
50     int mid = (l + r) >> 1;
51     int ans = 0;
52     if (ua <= mid)
53         ans += query(l,mid,pos<<1,ua,ub);
54     if (ub > mid)
55         ans += query(mid+1,r,pos<<1|1,ua,ub);
56     return ans;
57 
58 }
59 int x[maxn],y[maxn];
60 int main(void)
61 {
62     #ifndef ONLINE_JUDGE
63         freopen("in.txt","r",stdin);
64     #endif
65     int t;
66     scanf ("%d",&t);
67     while(t--)
68     {
69         scanf ("%d",&n);
70         int tot = 0;
71         for (int i = 0; i < n; i++)
72         {
73             scanf ("%d%d",x+i,y+i);
74             a[tot++] = x[i];
75             a[tot++] = y[i];
76         }
77         sort(a,a+tot);
78         tot = unique(a,a+tot) - a;
79         for (int i = 0; i < n; i++)
80         {
81             x[i] = lower_bound(a,a+tot,x[i]) - a + 1;
82             y[i] = lower_bound(a,a+tot,y[i]) - a + 1;
83         }
84         int ans = 0;
85         update(1,tot,1,1,tot,0);
86         for (int i = n - 1; i >= 0; i--)
87         {
88             if (query(1,tot,1,x[i],y[i]) < y[i] - x[i] + 1)
89             {
90                 ans++;
91                 update(1,tot,1,x[i],y[i],1);
92             }
93         }
94         printf("%d\n",ans);
95     }
96     return 0;
97 }