ZOJ-Tournament(2018icpc青岛)

输入

2
3 1
4 3

输出

Impossible
2 1 4 3
3 4 1 2
4 3 2 1

题解 找规律+构造

#include<bits/stdc++.h>
using namespace std;
const int N = 1001;
int ch[N][N];
int lowbit(int x){
    return x & (-x);
}

int main(){
    int n,k;
    int T;
    cin>>T;
    while(T --){
        cin>>n>>k;
        
        if(k >= lowbit(n))cout<<"Impossible"<<endl;
        else{
            for(int i = 1;i <= n;i ++){
                ch[0][i] = i;
            }
            
            for(int t = 1;t <= k;){
                for(int k = t;k < 2 * t;k ++){
                    int offset = t;
                    for(int z = 1;z <= n;z += 2 * offset){
                        for(int j = z;j < z + offset;j ++){
                            ch[k][j] = ch[k - offset][j + offset];
                        }
                        for(int j = z + offset;j < z + 2 * offset;j ++){
                            ch[k][j] = ch[k - offset][j - offset];
                        }
                    }
                    
                }
                
                t *= 2;
            }
            for(int i = 1;i <= k;i ++){
                cout<<ch[i][1];
                for(int j = 2;j <= n;j ++){
                    cout<<" " << ch[i][j];
                }
                cout<<endl;
            }
        }
    }
    return 0;
}