1868A. Fill in the Matrix

constructive algorithms, implementation, 1300, https://codeforces.com/problemset/problem/1868/A

#include<bits/stdc++.h>
using namespace std;
int T,n,m,a;
int main(){
    scanf("%d",&T);
    while(T--){
        scanf("%d %d",&n,&m);
        if(m==1)
            printf("0\n");
        else
            printf("%d\n",min(n+1,m));
        for(int i=1;i<=n;i++){
            a=m-i;
            if(a<=0)
                a=m-1;
            for(int j=1;j<=m;j++){
                printf("%d ",a);
                a=(a+1)%m;
            }
            printf("\n");
        }
    }
    return 0;
}