HDU 4430 Yukari's Birthday 【二分查找】
Yukari's Birthday
Time Limit: 12000/6000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5676 Accepted Submission(s): 1370
Problem Description
Today is Yukari's n-th birthday. Ran and Chen hold a celebration party for her. Now comes the most important part, birthday cake! But it's a big challenge for them to place n candles on the top of the cake. As Yukari has lived for such a long long time, though
she herself insists that she is a 17-year-old girl.
To make the birthday cake look more beautiful, Ran and Chen decide to place them like r ≥ 1 concentric circles. They place ki candles equidistantly on the i-th circle, where k ≥ 2, 1 ≤ i ≤ r. And it's optional to place at most one candle at the center of the cake. In case that there are a lot of different pairs of r and k satisfying these restrictions, they want to minimize r × k. If there is still a tie, minimize r.
To make the birthday cake look more beautiful, Ran and Chen decide to place them like r ≥ 1 concentric circles. They place ki candles equidistantly on the i-th circle, where k ≥ 2, 1 ≤ i ≤ r. And it's optional to place at most one candle at the center of the cake. In case that there are a lot of different pairs of r and k satisfying these restrictions, they want to minimize r × k. If there is still a tie, minimize r.
Input
There are about 10,000 test cases. Process to the end of file.
Each test consists of only an integer 18 ≤ n ≤ 1012.
Each test consists of only an integer 18 ≤ n ≤ 1012.
Output
For each test case, output r and k.
Sample Input
18 111 1111
Sample Output
1 17 2 10 3 10
Source
这个题有个比较坑的地放就是二分太大的时候会爆long long需要控制好上界
可以用ll high = pow(n, (double)1.0 / r);来紧上界防止爆long long
也可以在过程中判断long long是否溢出来解决
第一种做法:
#include<iostream> #include<algorithm> #include<cmath> #include<cstdio> #include<cstdlib> #include<queue> #include<map> #include<set> #include<stack> #include<bitset> #include<numeric> #include<vector> #include<string> #include<iterator> #include<cstring> #include<functional> #define INF 0x3f3f3f3f #define ms(a,b) memset(a,b,sizeof(a)) using namespace std; const int maxn = 10010; const int mod = 1e9 + 7; const double pi = acos(-1.0); typedef pair<int, int> P; typedef long long ll; typedef unsigned long long ull; int main() { ll n; while (~scanf("%lld", &n)) { ll ans = n - 1, ans1 = 1, ans2 = n - 1; for (int r = 2; r <= 41; r++) { ll low = 1; ll high = pow(n, (double)1.0 / r); ll mid; while (low <= high) { mid = (low + high) >> 1; ll tmp = 1, sum = 0; for (int i = 1; i <= r; i++) { tmp *= mid; sum += tmp; } if (sum == n || sum == (n - 1)) { if (mid*r < ans) { ans = mid*r; ans1 = r; ans2 = mid; } } if (sum > n) { high = mid - 1; } else { low = mid + 1; } } } printf("%lld %lld\n", ans1, ans2); } }
第二种做法:
#include<iostream> #include<algorithm> #include<cmath> #include<cstdio> #include<cstdlib> #include<queue> #include<map> #include<set> #include<stack> #include<bitset> #include<numeric> #include<vector> #include<string> #include<iterator> #include<cstring> #include<functional> #define INF 0x3f3f3f3f #define ms(a,b) memset(a,b,sizeof(a)) using namespace std; const int maxn = 10010; const int mod = 1e9 + 7; const double pi = acos(-1.0); typedef pair<int, int> P; typedef long long ll; typedef unsigned long long ull; int main() { ll n; while (~scanf("%lld", &n)) { ll ans = n - 1, ans1 = 1, ans2 = n - 1; for (int r = 2; r <= 41; r++) { ll low = 1; ll high = n - 1; ll mid; while (low <= high) { mid = (low + high) >> 1; ll tmp = 1, sum = 0; bool flag = 0; for (int i = 1; i <= r; i++) { if (tmp > (n / mid)) { flag = 1; break; } tmp *= mid; sum += tmp; } if (!flag&&(sum == n || sum == (n - 1))) { if (mid*r < ans) { ans = mid*r; ans1 = r; ans2 = mid; } } if (flag||sum > n) { high = mid - 1; } else { low = mid + 1; } } } printf("%lld %lld\n", ans1, ans2); } }
Fighting~