BZOJ2298: [HAOI2011]problem a

 1 #include<cstdio>
 2 
 3 #include<cstdlib>
 4 
 5 #include<cmath>
 6 
 7 #include<cstring>
 8 
 9 #include<algorithm>
10 
11 #include<iostream>
12 
13 #include<vector>
14 
15 #include<map>
16 
17 #include<set>
18 
19 #include<queue>
20 
21 #include<string>
22 
23 #define inf 1000000000
24 
25 #define maxn 200000+5
26 
27 #define maxm 200000+5
28 
29 #define eps 1e-10
30 
31 #define ll long long
32 
33 #define pa make_pair
34 
35 #define for0(i,n) for(int i=0;i<=(n);i++)
36 
37 #define for1(i,n) for(int i=1;i<=(n);i++)
38 
39 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
40 
41 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
42 
43 #define for4(i,x) for(int i=head[x],y=e[i].go;i;i=e[i].next,y=e[i].go)
44 
45 #define for5(n,m) for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)
46 
47 #define mod 1000000007
48 
49 using namespace std;
50 
51 inline int read()
52 
53 {
54 
55     int x=0,f=1;char ch=getchar();
56 
57     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
58 
59     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
60 
61     return x*f;
62 
63 }
64 int n,f[maxn];
65 vector<int>a[maxn];
66 map<pair<int,int>,int>mp;
67 
68 int main()
69 
70 {
71 
72     freopen("input.txt","r",stdin);
73 
74     freopen("output.txt","w",stdout);
75 
76     n=read();
77     for1(i,n)
78     {
79         int x=read(),y=read();
80         x++;y=n-y;
81         if(x>y)continue;
82         mp[pa(x,y)]++;
83         if(mp[pa(x,y)]==1)a[y].push_back(x);
84     }
85     for1(i,n)
86     {
87         f[i]=f[i-1];
88         for(int j=0,k=a[i].size();j<k;j++)
89          f[i]=max(f[i],f[a[i][j]-1]+min(mp[pa(a[i][j],i)],i-a[i][j]+1));
90     }
91     cout<<n-f[n]<<endl;
92 
93     return 0;
94 
95 }