MRECAMAN - Recaman’s Sequence
Tác giả: happyboy99x
Ngôn ngữ: C++
#include<cstdio>
#include<set>
using namespace std;
#define K 500000
int a[K+1], k;
int main() {
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
#endif
set<int> my;
for(int i = 1; i <= K; ++i) {
a[i] = a[i-1] - i;
if(a[i] <= 0 || a[i] > 0 && my.find(a[i]) != my.end())
a[i] = a[i-1] + i;
my.insert(a[i]);
}
while(scanf("%d", &k) != EOF && k != -1)
printf("%d\n", a[k]);
return 0;
}