第二十周 1.10-1.16

考完来补了。讲道理的话考试周还属于学期里阿。

1.10-1.13

中间打了场CF edu。

1.14

鸡场补题boy。

CF 616 E Sum of Remainders

式子变成mn-sigma(n/i*i)就是n^0.5的搞。

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long LL;
const LL mod = 1e9 + 7;

int main(void)
{
    LL n, m, tmp = 0LL, rev = 500000004LL;
    scanf("%I64d%I64d", &n, &m);
    LL p = min(m, n);
    for(LL i = 1; i <= p; i++)
    {
        LL r = min(p, n / ( n / i ) );
        tmp = ( tmp + (i + r) % mod * ( (r - i + 1LL) % mod ) % mod * rev % mod * (n / i) % mod ) % mod;
        i = r;
    }
    printf("%I64d
", ( m % mod * ( n % mod ) % mod - tmp + mod ) % mod );
    return 0;
}

1.15

打个CF。

CF 614 C Peter and Snow Blower

讨厌计几。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
const double pi = acos(-1);
const double INF = 1e18;
const int maxn = 1e5 + 10;
LL x, y, xx[maxn], yy[maxn];

double P2S(int i, int j)
{
    LL vx[4], vy[4];
    vx[1] = xx[j] - xx[i];
    vy[1] = yy[j] - yy[i];
    vx[2] = x - xx[i];
    vy[2] = y - yy[i];
    vx[3] = x - xx[j];
    vy[3] = y - yy[j];
    if( vx[1] * vx[2] + vy[1] * vy[2] < 0 ) return vx[2] * vx[2] + vy[2] * vy[2];
    if( vx[1] * vx[3] + vy[1] * vy[3] > 0 ) return vx[3] * vx[3] + vy[3] * vy[3];
    return 1.0 * ( vx[1] * vy[2] - vx[2] * vy[1] ) * ( vx[1] * vy[2] - vx[2] * vy[1] ) / ( vx[1] * vx[1] + vy[1] * vy[1] );
}

int main(void)
{
    int n;
    double Min = INF, Max = -1;
    scanf("%d%I64d%I64d", &n, &x, &y);
    for(int i = 0; i < n; i++)
    {
        scanf("%I64d%I64d", xx + i, yy + i);
        double d = (xx[i] - x) * (xx[i] - x) + (yy[i] - y) * (yy[i] - y);
        Max = max(Max, d);
    }
    for(int i = 0, j = n - 1; i < n; j = i++) Min = min(Min, P2S(i, j));
    printf("%.12lf
",pi * (Max - Min));
    return 0;
}

1.16

CF 614 D Skills

尺取。初始化跪RE了QAQ

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long LL;
const int maxn = 1e5 + 10;
LL cpy[maxn], sum[maxn];
struct node{int id; LL a;} ori[maxn];
bool cmp(node A, node B){return A.a < B.a;}

int main(void)
{
    int n, p1 = 0, ap1 = 0, ap2 = n + 1;
    LL cf, cm, A, m, ans = 0LL, tmp, Min;
    scanf("%d%I64d%I64d%I64d%I64d", &n, &A, &cf, &cm, &m);
    for(int i = 1; i <= n; i++)
    {
        scanf("%I64d", &ori[i].a);
        ori[i].id = i;
        cpy[i] = ori[i].a;
    }
    sort(ori + 1, ori + 1 + n, cmp);
    for(int i = 1; i <= n; i++) sum[i] = sum[i-1] + ori[i].a;
    for(int p2 = 2; p2 <= n + 1; p2++)
    {
        LL c = A * (n - p2 + 1) - sum[n] + sum[p2-1];
        if(c > m) continue;
        tmp = cf * (n - p2 + 1);
        LL l = m - c;
        while( p1 < p2 - 1 && ori[p1+1].a * (p1 + 1) - sum[p1+1] <= l ) p1++;
        l -= ori[p1].a * p1 - sum[p1];
        if( ori[p1].a + l / p1 < A) tmp += (ori[p1].a + l / p1) * cm;
        else tmp += A * cm + cf * p1;
        if(tmp > ans) ans = tmp, ap1 = p1, ap2 = p2, Min = min(A, ( ori[p1].a + l / p1 ));
    }
    for(int i = 1; i <= ap1; i++) cpy[ori[i].id] = Min;
    for(int i = ap2; i <= n; i++) cpy[ori[i].id] = A;
    printf("%I64d
", ans);
    for(int i = 1; i <= n; i++) printf("%I64d ", cpy[i]);
    puts("");
    return 0;
}