Codeforces Round #337 (Div. 2) C. Harmony Analysis 数学
The semester is already ending, so Danil made an effort and decided to visit a lesson on harmony analysis to know how does the professor look like, at least. Danil was very bored on this lesson until the teacher gave the group a simple task: find 4 vectors in 4-dimensional space, such that every coordinate of every vector is 1 or - 1 and any two vectors are orthogonal. Just as a reminder, two vectors in n-dimensional space are considered to be orthogonal if and only if their scalar product is equal to zero, that is:
Danil quickly managed to come up with the solution for this problem and the teacher noticed that the problem can be solved in a more general case for 2k vectors in 2k-dimensinoal space. When Danil came home, he quickly came up with the solution for this problem. Can you cope with it?
The only line of the input contains a single integer k (0 ≤ k ≤ 9).
Print 2k lines consisting of 2k characters each. The j-th character of the i-th line must be equal to ' * ' if the j-th coordinate of the i-th vector is equal to - 1, and must be equal to ' + ' if it's equal to + 1. It's guaranteed that the answer always exists.
If there are many correct answers, print any.
2
++**
+*+*
++++
+**+
Consider all scalar products in example:
- Vectors 1 and 2: ( + 1)·( + 1) + ( + 1)·( - 1) + ( - 1)·( + 1) + ( - 1)·( - 1) = 0
- Vectors 1 and 3: ( + 1)·( + 1) + ( + 1)·( + 1) + ( - 1)·( + 1) + ( - 1)·( + 1) = 0
- Vectors 1 and 4: ( + 1)·( + 1) + ( + 1)·( - 1) + ( - 1)·( - 1) + ( - 1)·( + 1) = 0
- Vectors 2 and 3: ( + 1)·( + 1) + ( - 1)·( + 1) + ( + 1)·( + 1) + ( - 1)·( + 1) = 0
- Vectors 2 and 4: ( + 1)·( + 1) + ( - 1)·( - 1) + ( + 1)·( - 1) + ( - 1)·( + 1) = 0
- Vectors 3 and 4: ( + 1)·( + 1) + ( + 1)·( - 1) + ( + 1)·( - 1) + ( + 1)·( + 1) = 0
题意:给 k,构造2^k * 2^k的图, 使得任意两行 相乘相加值为0
题解:对于一个 满足了条件的 正方形,想要得到将其边长翻倍的图形 我们将它复制接右边,接到正下方,再取反接到斜对角,就是了;
根据这个我们从1*1得到 2*2得到 4*4---到答案
//meek///#include<bits/stdc++.h> #include <cstdio> #include <cmath> #include <cstring> #include <algorithm> #include<iostream> #include<bitset> #include<vector> #include <queue> #include <map> #include <set> #include <stack> using namespace std ; #define mem(a) memset(a,0,sizeof(a)) #define pb push_back #define fi first #define se second #define MP make_pair typedef long long ll; const int N = 2000; const int M = 1000001; const int inf = 0x3f3f3f3f; const int MOD = 1000000007; const double eps = 0.000001; int a[N][N],n; int main() { scanf("%d",&n); a[0][0]=1; for(int x=1;x<=n;x++) { for(int i=0;i<(1<<x-1);i++) { for(int j=0;j<(1<<x-1);j++) { a[i][j+(1<<x-1)]=a[i][j]; a[i+(1<<x-1)][j]=a[i][j]; a[i+(1<<x-1)][j+(1<<x-1)]=1-a[i][j]; } } } for(int i=0;i<(1<<n);i++) { for(int j=0;j<(1<<n);j++) { if(a[i][j])printf("+"); else printf("*"); } printf("\n"); } return 0; }