poj2081

简单题

View Code

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxn 500004

int f[maxn];
bool vis[maxn * 10];

int main()
{
// freopen("t.txt", "r", stdin);
memset(vis, 0, sizeof(vis));
f[0] = 0;
for (int i = 1; i < maxn; i++)
{
f[i] = f[i - 1] - i > 0 && !vis[f[i - 1] - i]? f[i - 1] - i : f[i - 1] + i;
vis[f[i]] = true;
}
int n;
while (scanf("%d", &n), n != -1)
printf("%d\n", f[n]);
return 0;
}

转载于:https://www.cnblogs.com/rainydays/archive/2011/06/06/2073818.html