两两内积为0（牛客多校第七场）--CDMA

题意：

构造一个n*n的矩阵，元素只能是-1或1，任意两行内积为0（两两相乘加起来和为0）。

思路；

 #define IOS ios_base::sync_with_stdio(0); cin.tie(0);

 #include <cstdio>//sprintf islower isupper

 #include <cstdlib>//malloc  exit strcat itoa system("cls")

 #include <iostream>//pair

 #include <fstream>

 #include <bitset>

 //#include <map>

 //#include<unordered_map>

 #include <vector>

 #include <stack>

 #include <set>

 #include <string.h>//strstr substr

 #include <string>

 #include <time.h>//srand(((unsigned)time(NULL))); Seed n=rand()%10 - 0~9;

 #include <cmath>

 #include <deque>

 #include <queue>//priority_queue<int, vector<int>, greater<int> > q;//less

 #include <vector>//emplace_back

 //#include <math.h>

 //#include <windows.h>//reverse(a,a+len);// ~ ! ~ ! floor

 #include <algorithm>//sort + unique : sz=unique(b+1,b+n+1)-(b+1);+nth_element(first, nth, last, compare)

 using namespace std;//next_permutation(a+1,a+1+n);//prev_permutation

 #define fo(a,b,c) for(register int a=b;a<=c;++a)

 #define fr(a,b,c) for(register int a=b;a>=c;--a)

 #define mem(a,b) memset(a,b,sizeof(a))

 #define pr printf

 #define sc scanf

 #define ls rt<<1

 #define rs rt<<1|1

 void swapp(int &a,int &b);

 double fabss(double a);

 int maxx(int a,int b);

 int minn(int a,int b);

 int Del_bit_1(int n);

 int lowbit(int n);

 int abss(int a);

 //const long long INF=(1LL<<60);

 const double E=2.718281828;

 const double PI=acos(-1.0);

 const int inf=(<<);

 const double ESP=1e-;

 const int mod=(int)1e9+;

 const int N=(int)1e6+;

 int mp[][];

 void same(int cnt)

 {

     fo(i,,cnt)

     {

         fo(j,,cnt)

         {

             mp[i][j+cnt]=mp[i][j];

         }

     }

 }

 void _(int cnt)

 {

     fo(i,cnt+,cnt*-)

     {

         fo(j,,cnt)

             mp[i][j]=mp[i-cnt+][j];

         fo(j,cnt+,cnt*)

             mp[i][j]=-mp[i-cnt+][j];

     }

     fo(i,,cnt)

         mp[cnt*][i]=;

     fo(i,cnt+,cnt*)

         mp[cnt*][i]=;

 }

 int main()

 {

     mp[][]=mp[][]=mp[][]=;

     int cnt=;

     fo(i,,)

     {

         same(cnt);

         _(cnt);

         cnt*=;

     }

     int n;

     sc("%d",&n);

     fo(i,,n)

         fo(j,,n)

             pr("%d%c",mp[i][j]==?mp[i][j]:-,j==n?'\n':' ');

     return ;

 }

 /**************************************************************************************/

 int maxx(int a,int b)

 {

     return a>b?a:b;

 }

 void swapp(int &a,int &b)

 {

     a^=b^=a^=b;

 }

 int lowbit(int n)

 {

     return n&(-n);

 }

 int Del_bit_1(int n)

 {

     return n&(n-);

 }

 int abss(int a)

 {

     return a>?a:-a;

 }

 double fabss(double a)

 {

     return a>?a:-a;

 }

 int minn(int a,int b)

 {

     return a<b?a:b;

 }