PAT (Advanced Level) Practice - 1143 Lowest Common Ancestor（30 分）

#include<bits/stdc++.h>#include<cmath>#define mem(a,b) memset(a,b,sizeof a)#define ssclr(ss) ss.clear(), ss.str("")#define INF 0x3f3f3f3f#define MOD 1000000007usingnamespacestd;
typedeflonglongll;
unordered_map<int,int>ump;
intmain()
{
intq,n,a,u,v,pre[10009];
scanf("%d%d",&q,&n);
for(inti=0;i<n;i++) scanf("%d",&pre[i]), ump[pre[i]]=1;
while(q--)
    {
scanf("%d%d",&u,&v);
for(inti=0;i<n;i++)
        {
a=pre[i];
if(a>=u&&a<=v||a>=v&&a<=u) break;
        }
if(ump[u]==0&&ump[v]==0) printf("ERROR: %d and %d are not found.\n",u,v);
elseif(ump[u]==0||ump[v]==0) printf("ERROR: %d is not found.\n",ump[u]==0?u:v);
elseif(a==u||a==v) printf("%d is an ancestor of %d.\n",a,a==u?v:u);
elseprintf("LCA of %d and %d is %d.\n",u,v,a);
    }
return0;
}