Let’s Chat
解题思路
给定若干区间 [l, r] 分别表示 A 和 B 在区间内每一天均向对方发送信息。求有多少个不同的连续区间 [i,i−m+1] ，A 和 B 在区间的每一天均向对方发送了信息。
设MAX=max(b, L[i]), MIN=min(c,R[i]),当MIN-MAX-m>0时为并区间,且MIN-MAX-m的值为区间个数
题目描述
ACM (ACMers’ Chatting Messenger) is a famous instant messaging software developed by Marjar Technology Company. To attract more users, Edward, the boss of Marjar Company, has recently added a new feature to the software. The new feature can be described as follows:
If two users, A and B, have been sending messages to each other on the last m consecutive days, the “friendship point” between them will be increased by 1 point.
More formally, if user A sent messages to user B on each day between the (i - m + 1)-th day and the i-th day (both inclusive), and user B also sent messages to user A on each day between the (i - m + 1)-th day and the i-th day (also both inclusive), the “friendship point” between A and B will be increased by 1 at the end of the i-th day.
Given the chatting logs of two users A and B during n consecutive days, what’s the number of the friendship points between them at the end of the n-th day (given that the initial friendship point between them is 0)?
Input
There are multiple test cases. The first line of input contains an integer T (1 ≤ T ≤ 10), indicating the number of test cases. For each test case:
The first line contains 4 integers n (1 ≤ n ≤ 109), m (1 ≤ m ≤ n), x and y (1 ≤ x, y ≤ 100). The meanings of n and m are described above, while x indicates the number of chatting logs about the messages sent by A to B, and y indicates the number of chatting logs about the messages sent by B to A.
For the following x lines, the i-th line contains 2 integers la, i and ra, i (1 ≤ la, i ≤ ra, i ≤ n), indicating that A sent messages to B on each day between the la, i-th day and the ra, i-th day (both inclusive).
For the following y lines, the i-th line contains 2 integers lb, i and rb, i (1 ≤ lb, i ≤ rb, i ≤ n), indicating that B sent messages to A on each day between the lb, i-th day and the rb, i-th day (both inclusive).
It is guaranteed that for all 1 ≤ i < x, ra, i + 1 < la, i + 1 and for all 1 ≤ i < y, rb, i + 1 < lb, i + 1.
Output
For each test case, output one line containing one integer, indicating the number of friendship points between A and B at the end of the n-th day.
Sample Input
2
10 3 3 2
1 3
5 8
10 10
1 8
10 10
5 3 1 1
1 2
4 5
Sample Output
3
0
Hint
For the first test case, user A and user B send messages to each other on the 1st, 2nd, 3rd, 5th, 6th, 7th, 8th and 10th day. As m = 3, the friendship points between them will be increased by 1 at the end of the 3rd, 7th and 8th day. So the answer is 3.
AC代码
#include <cstdio>
#include <iostream>
#include <algorithm>
using namespace std;
int l[105], r[105];
int main()
{
int t;
//freopen("input.txt", "r", stdin);
while(~scanf("%d",&t))
{
while(t--)
{
int n, m, x, y;
scanf("%d%d%d%d",&n,&m,&x,&y);
m-=2; //注意这里的处理
for(int i=0; i<x; i++)
scanf("%d%d",&l[i],&r[i]);
int sum = 0;
for(int i=0; i<y; i++)
{
int b,c;
scanf("%d%d",&b,&c);
for(int j=0; j<x; j++)
{
int MAX=max(l[j],b);
int MIN=min(r[j],c);
if(MIN-MAX-m>0)
sum += MIN-MAX-m;
}
}
printf("%d\n",sum);
}
}
return 0;
}