http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1087

暴力大法

#include
     
      using namespace std;map 
      
       s;void solve(){    int i=1,k=1;    while (i<=1e9)    {        s[i] = 1;        i+=k;        k++;    }}int main (){    int t,n;    solve();scanf("%d",&t);    while (t--){        scanf("%d",&n);        printf("%d\n",s[n]);    }}
      
     

 

 

百度 an - an-1 = n-1 就可以知道通项公式

然后 用公式算

#include
     
      using namespace std;int main (){    int t,n;    scanf("%d",&t);    while (t--){        scanf("%d",&n);        int t = sqrt(2*n-2);        if(t * (t+1) == 2*n-2)            printf("1\n");        else            printf("0\n");    }}