【1】【匹配】HDU5821 Ball

Ball

Time Limit: 2000/1000 MS (Java/Others)
Memory Limit: 65536/65536 K (Java/Others)

Problem Description
ZZX has a sequence of boxes numbered 1,2,…,n. Each box can contain at most one ball.

You are given the initial configuration of the balls. For 1≤i≤n, if the i-th box is empty then a[i]=0, otherwise the i-th box contains exactly one ball, the color of which is a[i], a positive integer. Balls with the same color cannot be distinguished.

He will perform m operations in order. At the i-th operation, he collects all the balls from boxes l[i],l[i]+1,…,r[i]-1,r[i], and then arbitrarily put them back to these boxes. (Note that each box should always contain at most one ball)

He wants to change the configuration of the balls from a[1..n] to b[1..n] (given in the same format as a[1..n]), using these operations. Please tell him whether it is possible to achieve his goal.

Input
First line contains an integer t. Then t testcases follow.
In each testcase: First line contains two integers n and m. Second line contains a[1],a[2],…,a[n]. Third line contains b[1],b[2],…,b[n]. Each of the next m lines contains two integers l[i],r[i].

1<=n<=1000,0<=m<=1000, sum of n over all testcases <=2000, sum of m over all testcases <=2000.

0<=a[i],b[i]<=n.

1<=l[i]<=r[i]<=n.

Output
For each testcase, print “Yes” or “No” in a line.

Sample Input
5
4 1
0 0 1 1
0 1 1 1
1 4
4 1
0 0 1 1
0 0 2 2
1 4
4 2
1 0 0 0
0 0 0 1
1 3
3 4
4 2
1 0 0 0
0 0 0 1
3 4
1 3
5 2
1 1 2 2 0
2 2 1 1 0
1 3
2 4

Sample Output
No
No
Yes
No
Yes

链接
HDU5821

题意
有n个盒子，每个盒子最多放1个球，球有多种颜色，用1~n的不同数字表示。现在给出两种状态a,b和m个操作区间[l,r]，操作过程为：将区间中的球全都拿出，然后随机地放回去。问状态a经过m次操作能否到达b状态。

分析
16/8/11最开始想到的是拿两组状态从1~m区间sort，但是一直wa，后来听了题解也不是很明白。大概理解是把两组状态整体sort，然后记录sort后的对应位置，再拿对应位置进行区间sort，使a状态中的每个数都到达b状态中最近的位置，若sort结果一一对应表示sort后的a状态可达到sort后的b状态，即a可达b（我自己都被自己讲晕了= =）。