E. Construct the Binary Tree（构造二叉树）

http://codeforces.com/problemset/problem/1311/E

题意：

构造一棵深度和为d的二叉树

解析：

先排成一条链，然后每次把最深的点往上提就行

代码：

/*
 *  Author : Jk_Chen
 *    Date : 2020-03-10-10.54.52
 */
#include<bits/stdc++.h>
using namespace std;
#define LL long long
#define rep(i,a,b) for(int i=(int)(a);i<=(int)(b);i++)
#define per(i,a,b) for(int i=(int)(a);i>=(int)(b);i--)
#define mmm(a,b) memset(a,b,sizeof(a))
#define pb push_back
#define pill pair<int, int>
#define fi first
#define se second
#define debug(x) cerr<<#x<<" = "<<x<<'\n'
const LL mod=1e9+7;
const int maxn=5009;
const int inf=0x3f3f3f3f;
LL rd(){ LL ans=0; char last=' ',ch=getchar();
    while(!(ch>='0' && ch<='9'))last=ch,ch=getchar();
    while(ch>='0' && ch<='9')ans=ans*10+ch-'0',ch=getchar();
    if(last=='-')ans=-ans; return ans;
}
#define rd rd()
/*_________________________________________________________begin*/

int a[maxn];

int main(){
    int t=rd;
    while(t--){
        int n=rd,m=rd;
        mmm(a,0);
        rep(i,0,n-1)a[i]=1;
        int d=(n-1)*n/2;
        if(d<m){
            puts("NO");continue;
        }
        int mx=n-1;
        while(d>m&&mx){
            int hav=0;
            int to=max(1,mx-(d-m));
            rep(i,to,mx-1){
                if(a[i]+1<=2*a[i-1]){
                    hav=1;
                    d-=mx-i;
                    a[mx]--;
                    a[i]++;
                    break;
                }
            }
            if(!hav)mx--;
            else{
                if(a[mx]==0)mx--;
            }
        }
        if(d!=m){puts("NO");continue;}
        puts("YES");
        vector<int>V;
        V.pb(1);
        int cnt=1;
        rep(i,1,n-1){
            if(a[i]==0)break;
            rep(j,0,a[i]-1){
                printf("%d ",V[j/2]);
            }
            V.clear();
            rep(j,1,a[i]){
                V.pb(++cnt);
            }
        }
        puts("");
    }

    return 0;
}

/*_________________________________________________________end*/