HDU 1541 & POJ 2352 Stars (樹狀陣列)

Mr_Treeeee發表於2020-04-06
陣列

Stars

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 9874    Accepted Submission(s): 3959


Problem Description
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
5
1 1
5 1
7 1
3 3
5 5





 



Sample Output




1
2
1
1
0





 



Source



Ural Collegiate Programming Contest 1999 



 


題意：


給你一個二維的星星圖，讓你求出每個星星的左下有幾顆星星並輸出有（0-n-1）顆星星的數量。


POINT：


由於題目是按照y遞增的順序給出星星，就直接記錄x位置星星有幾顆，樹狀陣列記錄區間(1-x)星星有幾顆就行了。





#include <stdio.h>
#include <string.h>
#include <iostream>
#include <map>
#include <algorithm>
using namespace std;
#define rt x<<1|1
#define lt x<<1
const int N = 32000*10;
#define  LL long long
int sum[N];
int n;
int maxn;
int lowbit(int x)
{
    return x&-x;
}
void add(int x,int c)
{
    while(x<=32001)
    {
        sum[x]+=c;
        x+=lowbit(x);
    }
}
int query(int x)
{
    int ans=0;
    while(x>=1)
    {
        ans+=sum[x];
        x-=lowbit(x);
    }
    return ans;
}
int main()
{
    int ans[15010];
    while(~scanf("%d",&n))
    {
        memset(sum,0,sizeof sum);
        memset(ans,0,sizeof ans);
        int x;
        int y;
        for(int i=1;i<=n;i++)
        {
            scanf("%d %d",&x,&y);
            ans[query(x+1)]++;
            add(x+1,1);
        }
        for(int i=0;i<n;i++)
        {
            printf("%d\n",ans[i]);
        }
    }
    return 0;
}



                                    




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