51nod 1346: Recursive

Source: Internet
Author: User

1346 recursive base time limit: 1 second space limit: 131072 KB score: 80 Difficulty: 5-level algorithm topic collection attention

function f (n,m)

{

If N=1 or M=1 returns to A[n][m];

Returns f (N-1,m) Xor F (n,m-1);

}

Read in 2<=n,m<=100

For i=2->100 read in A[1][i]

For i=2->100 read in a[i][1]

Output f (n,m)

It is found that the program becomes unusually slow when the n,m is larger.

Small B After some thinking, soon solved the problem.

At this time small C appeared, I will n,m all increase 131072, you still can solve?

In contrast, I will read all the a[1][i] and a[i][1 in 2->131172).

Small b made a difficult, so come to you, can you help him?

Input
The first line reads in 131,171 positive integers, representing i=2->131172 's a[1][i] (1<=a[1][i]<=1000000000). The second line reads in 131,171 positive integers, representing i=2->131172 's a[i][1] (1<=a[i][1]<=1000000000). The third line reads a positive integer, Q (1<=q<=10000), indicating the number of queries. The next Q line, two numbers per line n,m (2<=n,m<=100), represents each group of queries.
Output
Q Line, per action F (n+131072,m+131072)
Input example
2 3 4 5 6 7 8 ... 131171 1311722 3 4 5 6 7 8 ... 131171 13117232 22) 32 4
Output example
00131072

A[i][j]=a[i-1][j]^a[i][j-1]=a[i-2][j]^a[i-1][j-1]^a[i-1][j-1]^a[i][j-2]=a[i-2][j]^a[i][j-2]

A[I][J]=A[I-2][J]^A[I][J-2]=A[I-4][J]^A[I-2][J-2]^A[I-2][J-2]^A[I][J-4]=A[I-4][J]^A[I][J-4]

And so on you can find

A[I][J]=A[I-131072][J]^A[I][J-131072]

Pretreatment a[1..100][1..131172] and a[1..131172][1..100]

For each query answer is A[N][131072+M]^A[131072+N][M]


I think 51nod's topic is really interesting, of course, if it's not so difficult math problems, I would feel more interesting.

At that time has been gradually introduced to the law, but the ability to read the problem is really deficient, and then another point is that the sense of pre-processing will be timed out, did not dare to do so, think it will be wrong (afraid of what Ah, do it again AH)

Code:

#include <iostream> #include <algorithm> #include <cmath> #include <vector> #include <string > #include <cstring> #pragma warning (disable:4996) using namespace Std;int a1[131175];int a2[131175];int r1[105 ][131175];int R2[131175][105];int Main () {int i,m,n,q;a1[1] = 0;a2[1] = 0;memset (r1, 0, sizeof (R1)), memset (R2, 0, sizeof (r 2)); for (i = 2; I <= 131172; i++) {scanf ("%d", &a1[i]); R1[1][i] = A1[i];if (i >= 2 && i <=) r2[1][i ] = A1[i];}  for (i = 2; I <= 131172; i++) {scanf ("%d", &a2[i]); r2[i][1] = A2[i];if (i >= 2 && i <=) r1[i][1] = A2[i];} for (M = 2; M <=, m++) {for (n = 2; n <= 131172;n++) {R1[m][n] = R1[m-1][n] ^ r1[m][n-1];}} for (M = 2, M <= 131172; m++) {for (n = 2; n <=, n++) {r2[m][n] = R2[m-1][n] ^ r2[m][n-1];}}  scanf ("%d", &q); for (i = 1; I <= Q; i++) {scanf ("%d%d", &n, &m); cout << (r1[n][131072 + m] ^ r2[131072 + n][m]) << Endl;} return 0;}





Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

51nod 1346: Recursive

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.