AtCoder Beginner Contest 100

A

直接算能被2整除的个数和。

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// LUOGU_RID: 174647527
#include <bits/stdc++.h>
using namespace std;
int n, a, ans;
int main()
{
    scanf("%d", &n);
    for (int i = 1; i <= n; i++)
    {
        scanf("%d", &a);
        while (a % 2 == 0)
            ans++, a /= 2; // 累加
    }
    printf("%d", ans);
    return 0;
}

B

直接暴力枚举符号进行排序。

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// LUOGU_RID: 174650112
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1005;
const int INF = 0x3f3f3f3f;
const long long LNF = 0x3f3f3f3f3f3f3f3f;
ll n, m;
ll i, j, k;
struct CAKE
{
    ll a;
    ll b;
    ll c;
} cake[MAXN];

bool cmp(CAKE a, CAKE b)
{
    return a.a * i + a.b * j + a.c * k > b.a * i + b.b * j + b.c * k;
}

int main()
{
    cin >> n >> m;
    for (i = 1; i <= n; i++)
        cin >> cake[i].a >> cake[i].b >> cake[i].c;
    ll ans = -LNF;
    for (i = -1; i <= 1; i += 2)
        for (j = -1; j <= 1; j += 2)
            for (k = -1; k <= 1; k += 2)
            {
                sort(cake + 1, cake + n + 1, cmp);
                ll tot[5] = {};
                for (int l = 1; l <= m; l++)
                {
                    tot[1] += cake[l].a;
                    tot[2] += cake[l].b;
                    tot[3] += cake[l].c;
                }
                ans = max(ans, tot[1] * i + tot[2] * j + tot[3] * k);
            }
    cout << ans << '\n';
    return 0;
}