HDU 5879 Cure 2016 ACM/ICPC Asia Regional Qingdao Online 1002

一道水题……坑的是没告诉N的范围。

N要用字符串输入然后转化为整数。

#include<stdio.h>#include<iostream>#include<memory.h>#include<stdlib.h>#include<cstdio>#include<cstring>#include<queue>#include<set>#include<algorithm>using namespace std;const int MAXN = 250000;const int INF = 0x3f3f3f3f;typedef long long LL;int T, N, M;double a[MAXN + 10];double final = 1.64493;char str[MAXN];int CalN(){N = 0;for (int i = 0; str[i]; i++){N = N * 10 + str[i] - '0';if (N > MAXN){N = MAXN;break;}}return N;}int main() {int i;double sum = 0.0;a[0] = 0;for (i = 1; i <= MAXN; i++){sum += 1.0 / i / i;a[i] = sum;}int T;while (scanf("%s", str) != EOF){N = CalN();printf("%.5lf\n", a[N]);}return 0;}