Educational Codeforces Round 26 D dp,思维

#include<bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define rep(i,a,b) for (int i=a; i<=b; ++i)
#define per(i,b,a) for (int i=b; i>=a; --i)
#define mes(a,b)  memset(a,b,sizeof(a))
#define INF 0x3f3f3f3f
#define MP make_pair
#define PB push_back
#define fi  first
#define se  second
typedef long long ll;
const int N = 200005;

int dp[210][6100], n, k;
int main()
{
    scanf("%d%d", &n, &k);
    ll  ai, a2, ans=0;
    int t2, t5;
    rep(j,0,200) rep(l,0,6000)
        dp[j][l] = -INF;
    dp[0][0] = 0;
    rep(i,1,n)
    {
        scanf("%lld", &ai);
        t2 = t5 = 0;
        for(a2=ai; a2%2==0; a2/=2, ++t2) ;
        for(a2=ai; a2%5==0; a2/=5, ++t5) ;
        per(j,k,1)   //????
        {
            rep(l,t5,6000)
            {
                dp[j][l] = max(dp[j][l], dp[j-1][l-t5]+t2);
                if(j==k) ans = max(ans, 1LL*min(l, dp[j][l]));
            }
        }
    }
    printf("%lld\n", ans);

    return 0;
}