CodeForces 830C Bamboo Partition

要求最大的d满足

∑ni=1d−((ai−1)%d+1)≤k

推出上下界

n×d−∑ni=1ai−⌊ai−1d⌋×d≤k

n×d+d∑ni=1⌊ai−1d⌋≤k+∑ni=1ai

枚举⌊ai−1d⌋的取值，乱搞就行了

#include <cstdio>#include <vector>#include <algorithm>#define C (c=getchar())#define ll long longusing namespace std;inline void read(int& a){    a=0;int f=1;static char c;C;    while (c<'0'||c>'9') {if (c=='-') f=-1;C;}    while (c>='0'&&c<='9') a=(a<<3)+(a<<1)+c-48,C;a*=f;}inline void read(ll& a){    a=0;int f=1;static char c;C;    while (c<'0'||c>'9') {if (c=='-') f=-1;C;}    while (c>='0'&&c<='9') a=(a<<3)+(a<<1)+c-48,C;a*=f;}int n,a[105];ll k,tot;vector<int> q;int main(){    register int i,j;    read(n),read(k);    for (i=1;i<=n;i++) read(a[i]),tot+=a[i]--;tot+=k;int d;     for (i=1;i<=n;i++)    for (j=1;j<=a[i];j=d+1)    d=a[i]/(a[i]/j),q.push_back(j);    for(i=1;i<=n;i++) q.push_back(a[i]+1);    sort(q.begin(),q.end());q.resize(unique(q.begin(),q.end())-q.begin());    int ans;    for (j=q.size()-1;j;j--)    {        d=q[j];ll tmp=0;        for (i=1;i<=n;i++)tmp+=d*(a[i]/d);        if (1ll*n*d+tmp<=tot) {ans=d;break;}    }    ll tmp=0;    for (i=1;i<=n;i++) tmp+=(a[i]/ans);    printf("%lld\n",tot/(n+tmp));}