hdu 4190（二分）

思路：二分答案每次验证一下是否可行。

代码如下：

/**************************************************
 * Author     : xiaohao Z
 * Blog     : http://www.cnblogs.com/shu-xiaohao/
 * Last modified : 2014-06-21 22:01
 * Filename     : hdu_4190.cpp
 * Description     : 
 * ************************************************/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#define MP(a, b) make_pair(a, b)
#define PB(a) push_back(a)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<unsigned int,unsigned int> puu;
typedef pair<int, double> pid;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;

const int INF = 0x3f3f3f3f;
const double eps = 1E-6;
const int LEN = 500000+10;
int n, m, num[LEN];

bool J(int val){
    ll ans = 0;
    for(int i=0; i<n; i++){
        int tmp = num[i]/val;
        if(num[i] % val) tmp++;
        ans += tmp;
    }
    if(ans <= m) return true;
    else return false;
}

int main()
{
//    freopen("in.txt", "r", stdin);

    ios::sync_with_stdio(false);
    while(cin >> n >> m){
        if(n == -1 && m == -1) break;
        int l = 1, r = 1;
        for(int i=0; i<n; i++){
            cin >> num[i];
            r = max(r, num[i]);
        }
        while(l < r){
            int mid = (l + r) / 2;
            if(J(mid)) r = mid;
            else l = mid + 1;
        }
        cout << l << endl;

    }
    return 0;
}