zoj 2421 Recaman's Sequence

//按题目要求求出其数列！用查表的方法很容易就可以实现！#include "iostream"#include "memory.h"using namespace std;int num[500010];int flag[10000100];//由于数组开小了，所以之前都运行不了！int main(){int k, i;memset(num, 0, sizeof(num));memset(flag, 0, sizeof(flag));num[0] = 0;for (i = 1; i < 500010; i++)//建立起表格！{num[i] = num[i-1] - i;if (num[i] <= 0 || flag[num[i]] == 1)num[i] = num[i-1] + i;flag[num[i]] = 1;}while (cin >> k && k != -1){cout << num[k] << endl;}}