标签：ble == string void include 表示 stdio.h statement maximum
Let‘s call the roundness of the number the number of zeros to which it ends.
You have an array of n numbers. You need to choose a subset of exactly k numbers so that the roundness of the product of the selected numbers will be maximum possible.
The first line contains two integer numbers n and k (1?≤?n?≤?200,?1?≤?k?≤?n).
The second line contains n space-separated integer numbers a1,?a2,?...,?an (1?≤?ai?≤?1018).
Print maximal roundness of product of the chosen subset of length k.
3 2
50 4 20
3
5 3
15 16 3 25 9
3
3 3
9 77 13
0
In the first example there are 3 subsets of 2 numbers. [50,?4] has product 200 with roundness 2, [4,?20] — product 80, roundness 1, [50,?20] — product 1000, roundness 3.
In the second example subset [15,?16,?25] has product 6000, roundness 3.
In the third example all subsets has product with roundness 0.
给你n个数，从中取k个数，求使得k个数相乘最多有多少个后缀0。
一个神奇的动态规划。dp[i][j]表示取i个数，在有j个5的情况下最多有多少个2
1 #include <iostream> 2 #include <stdio.h> 3 #include <string.h> 4 #include <algorithm> 5 #include <cmath> 6 #define ll long long 7 using namespace std; 8 struct Nod { 9 ll a; 10 int x,y; 11 Nod(){ 12 a = x = y = 0; 13 } 14 }nod[220]; 15 void fun(Nod *p) { 16 ll x = p->a; 17 while(x%2 == 0){ 18 p->x++; 19 x/=2; 20 } 21 x = p->a; 22 while(x%5 == 0){ 23 p->y++; 24 x/=5; 25 } 26 } 27 int dp[210][18*210]; 28 bool vis[220]; 29 int main() { 30 int n, k,MAXY=0; 31 cin >> n >> k; 32 for(int i = 1; i <= n; i ++) 33 cin >> nod[i].a, fun(&nod[i]),MAXY += nod[i].y; 34 memset(dp, -1, sizeof(dp)); 35 // for(int i = 1; i <= n; i ++)printf("%d %d\n",nod[i].x,nod[i].y); 36 // printf("%d\n",MAXY); 37 dp[0][0] = 0; 38 for(int i = 1; i <= n; i ++) { 39 for(int j = k; j >= 1; j --) { 40 for(int k = MAXY; k >= 0; k --) { 41 if(k-nod[i].y < 0) continue; 42 if(dp[j-1][k-nod[i].y] == -1) continue; 43 dp[j][k] = max(dp[j][k], dp[j-1][k-nod[i].y]+nod[i].x); 44 } 45 } 46 } 47 int ans = 0; 48 for(int i = 1; i <= MAXY; i ++) { 49 ans = max(ans, min(i,dp[k][i])); 50 } 51 printf("%d\n",ans); 52 return 0; 53 }
Educational Codeforces Round 26 D. Round Subset 动态规划
标签：ble == string void include 表示 stdio.h statement maximum
原文地址：http://www.cnblogs.com/xingkongyihao/p/7287091.html
