Stars POJ - 2352

最新推荐文章于 2022-03-19 16:31:18 发布

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最新推荐文章于 2022-03-19 16:31:18 发布

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原文链接：http://www.cnblogs.com/qldabiaoge/p/9415308.html

本文介绍了一个天文学中统计星图中各星等数量的问题，并提供了一段C++代码实现。该算法利用了离线数据结构来高效地计算每个星星左下方的星星数量，即星星的级别。

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Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a star be an amount of the stars that are not higher and not to the right of the given star. Astronomers want to know the distribution of the levels of the stars.

For example, look at the map shown on the figure above. Level of the star number 5 is equal to 3 (it's formed by three stars with a numbers 1, 2 and 4). And the levels of the stars numbered by 2 and 4 are 1. At this map there are only one star of the level 0, two stars of the level 1, one star of the level 2, and one star of the level 3.

You are to write a program that will count the amounts of the stars of each level on a given map.

Input

The first line of the input file contains a number of stars N (1<=N<=15000). The following N lines describe coordinates of stars (two integers X and Y per line separated by a space, 0<=X,Y<=32000). There can be only one star at one point of the plane. Stars are listed in ascending order of Y coordinate. Stars with equal Y coordinates are listed in ascending order of X coordinate.

Output

The output should contain N lines, one number per line. The first line contains amount of stars of the level 0, the second does amount of stars of the level 1 and so on, the last line contains amount of stars of the level N-1.

Sample Input

Sample Output

Hint

This problem has huge input data,use scanf() instead of cin to read data to avoid time limit exceed.

求一个star 左下角有多少星星

这个和求逆序对也差不多

几乎没有不同

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <queue>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <set>
 7 #include <iostream>
 8 #include <map>
 9 #include <stack>
10 #include <string>
11 #include <vector>
12 #define pi acos(-1.0)
13 #define eps 1e-6
14 #define fi first
15 #define se second
16 #define lson l,m,rt<<1
17 #define rson m+1,r,rt<<1|1
18 #define bug         printf("******\n")
19 #define mem(a,b)    memset(a,b,sizeof(a))
20 #define fuck(x)     cout<<"["<<x<<"]"<<endl
21 #define f(a)        a*a
22 #define sf(n)       scanf("%d", &n)
23 #define sff(a,b)    scanf("%d %d", &a, &b)
24 #define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
25 #define pf          printf
26 #define FRE(i,a,b)  for(i = a; i <= b; i++)
27 #define FREE(i,a,b) for(i = a; i >= b; i--)
28 #define FRL(i,a,b)  for(i = a; i < b; i++)
29 #define FRLL(i,a,b) for(i = a; i > b; i--)
30 #define FIN freopen("DATA.txt","r",stdin)
31 #define lowbit(x)   x&-x
32 #pragma comment (linker,"/STACK:102400000,102400000")
33 
34 using namespace std;
35 typedef long long LL ;
36 const int maxn = 4e4 + 10;
37 const int limit = 32010;
38 int n, c[maxn], lev[maxn];
39 void update(int x) {
40     while(x < 32010) {
41         c[x] += 1;
42         x += lowbit(x);
43     }
44 }
45 int sum(int x) {
46     int ret = 0;
47     while(x > 0) {
48         ret += c[x];
49         x -= lowbit(x);
50     }
51     return ret;
52 }
53 int main() {
54     scanf("%d", &n);
55     mem(c, 0);
56     mem(lev, 0);
57     for (int i = 1 ; i <= n ; i++) {
58         int x, y;
59         scanf("%d%d", &x, &y);
60         x++;
61         lev[sum(x)]++;
62         update(x);
63     }
64     for (int i = 0 ; i < n ; i++)
65         printf("%d\n", lev[i]);
66     return 0;
67 }