Codeforces 632D Longest Subsequence 【求因子和变形】
来源:互联网 发布:在家做淘宝客服兼职 编辑:程序博客网 时间:2024/05/17 22:23
You are given array a with n elements and the number m. Consider some subsequence of a and the value of least common multiple (LCM) of its elements. Denote LCM as l. Find any longest subsequence of a with the value l ≤ m.
A subsequence of a is an array we can get by erasing some elements of a. It is allowed to erase zero or all elements.
The LCM of an empty array equals 1.
The first line contains two integers n and m (1 ≤ n, m ≤ 106) — the size of the array a and the parameter from the problem statement.
The second line contains n integers ai (1 ≤ ai ≤ 109) — the elements of a.
In the first line print two integers l and kmax (1 ≤ l ≤ m, 0 ≤ kmax ≤ n) — the value of LCM and the number of elements in optimal subsequence.
In the second line print kmax integers — the positions of the elements from the optimal subsequence in the ascending order.
Note that you can find and print any subsequence with the maximum length.
7 86 2 9 2 7 2 3
6 51 2 4 6 7
6 42 2 2 3 3 3
2 31 2 3
fuck,偷懒用cin>>,T了。。。
题意:给定一个n元素构成的序列和一个数m,让你找到一个最长的子序列c[]使得lcm(c[]) <= m。输出序列的lcm 和 长度以及 组成这个序列的元素下标。
思路:发现m最大为10^6,可以直接暴力搞出i(1 <= i <= m)在序列中的因子数sum[i],就是求因子和的变形。
然后我们找到最大的sum[i],这个就是满足题意的子序列的最大长度。此时对应的i并不一定是子序列的lcm,我们就从末尾扫一次,对符合条件的元素求一次lcm即可。
AC代码:
#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#include <map>#include <string>#include <vector>#include <queue>#include <stack>#define CLR(a, b) memset(a, (b), sizeof(a))#define ll o<<1#define rr o<<1|1using namespace std;typedef long long LL;const int MOD = 1e9+7;const int MAXN = 1e6+10;const int INF = 0x3f3f3f3f;void add(LL &x, LL y) {x += y; x %= MOD;}map<LL, int> fp;LL gcd(LL a, LL b) { return b == 0 ? a : gcd(b, a%b);}LL lcm(LL a, LL b) { return a / gcd(a, b) * b;}LL a[MAXN]; int sum[MAXN];int main(){ int n, m; cin >> n >> m; fp.clear(); for(int i = 1; i <= n; i++) scanf("%lld", &a[i]), fp[a[i]]++; for(int i = 1; i <= m; i++) { if(i == 1) sum[i] = fp[1]; else sum[i] = fp[i] + fp[1]; } for(int i = 2; i*i <= m; i++) { for(int j = i; i*j <= m; j++) { if(i == j) sum[i*j] += fp[i]; else sum[i*j] += fp[i] + fp[j]; } } int ans = 0; LL Wlcm = 1LL; for(int i = m; i >= 1; i--) { if(sum[i] > ans) { Wlcm = i; ans = sum[i]; } //num[i] = 0; } LL Tlcm = 1LL; stack<int> S; for(int i = n; i >= 1; i--) { if(Wlcm % a[i] == 0) { Tlcm = lcm(Tlcm, a[i]); S.push(i); } } cout << Tlcm << " " << ans << endl; int num = 0; while(!S.empty()) { if(num) cout << " "; cout << S.top(); S.pop(); num++; } cout << endl; return 0;}
- Codeforces 632D Longest Subsequence 【求因子和变形】
- Codeforces-632D Longest Subsequence
- Codeforces 632D Longest Subsequence
- CodeForces 632D Longest Subsequence(数论)
- Longest Subsequence codeforces 632D 暴力数学
- [杂题] Codeforces #632D Longest Subsequence
- Longest Subsequence CodeForces 632D 数学/筛法
- CodeForces 546D (求素因子个数)
- Educational Codeforces Round 9(D. Longest Subsequence(筛法))
- Educational Codeforces Round 9-D. Longest Subsequence(筛选法)
- Educational Codeforces Round 9 D. Longest Subsequence CF632D
- CF 632D(Longest Subsequence-计数排序)
- CodeForces 546D Soldier and Number Game(求素因子+数学+前缀和)
- D. Longest Subsequence
- codeforces Longest Increasing Subsequence
- codeForces-Longest Subsequence
- Longest Subsequence CodeForces
- cf#ecr9-D - Longest Subsequence
- java调用第三方支付接口
- 计算指定时间与当前的时间差
- 【GDKOI2016】项链Code&Details
- ORCAD 创建原理图库
- 欢迎使用CSDN-markdown编辑器
- Codeforces 632D Longest Subsequence 【求因子和变形】
- Ubuntu14.04 软件源
- bzoj 1018 堵塞的交通
- 贪心解决最大最小公倍数问题
- java关键字之我见
- Cannot proceed with delivery: an existing transporter instance is currently uploading this package
- java----会动的方块
- mysql分表和表分区详解
- 几个容器