[树状数组] 树状数组基础练习题题解（五）

Time Limit: 1000MS
Memory Limit: 65536K

Contents

1 Description
2 Input
3 Output
4 Sample Input
5 Sample Output
6 Source

Description

Japan plans to welcome the ACM ICPC World Finals and a lot of roads must be built for the venue. Japan is tall island with N cities on the East coast and M cities on the West coast (M <= 1000, N <= 1000). K superhighways will be build. Cities on each coast are numbered 1, 2, … from North to South. Each superhighway is straight line and connects city on the East coast with city of the West coast. The funding for the construction is guaranteed by ACM. A major portion of the sum is determined by the number of crossings between superhighways. At most two superhighways cross at one location. Write a program that calculates the number of the crossings between superhighways.

Input

The input file starts with T – the number of test cases. Each test case starts with three numbers – N, M, K. Each of the next K lines contains two numbers – the numbers of cities connected by the superhighway. The first one is the number of the city on the East coast and second one is the number of the city of the West coast.

Output

For each test case write one line on the standard output:
Test case (case number): (number of crossings)

Sample Input

Sample Output

Test case 1: 5

Source

Southeastern Europe 2006

解题思路:将x作为第一关键字从小到大排序，如果相等则将y作为第二关键字从小到大排序。每次将y的编号插入树状数组中，输出有多少条公路y的编号大于当前公路y的编号

#include
#include
#include
#include
#include
#include
#define LL long long

using namespace std;
const int MAXN = 1010;

int n,m,k;
int tree[MAXN+10];

struct Data{
    int x;
    int y;
};

Data input[MAXN*MAXN];

inline bool cmp(Data a,Data b){
    if(a.x==b.x)
        return a.y<=b.y;
    return a.x