題意  把m數分成k組  使每組數的和的最大值最小  如果有多種分法 靠前的組的和儘量小

關鍵是找出那個最小的最大值   可以通過二分來找出  開始左端點為m個數中最大的數  右端點為m個數的和  若中點能將m個數分為小於等於k組  比它大的肯定都是可以的  中點變為右端點   否則中點變成左端點

然後就可以貪心逆向模擬了  從後往前每組選擇儘量多的數直到剩下的數等於組數 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 505;
int a[N], d[N], m, k, maxi;
ll s[N], le, ri, mid, mins, t;

int divs()
{
    int last = 0, cnt = 1;
    for(int i = 1; i <= m; ++i)
    {
        if(s[i] - s[last] > mid)
            last = i - 1, ++cnt;
    }
    return cnt;
}

int main()
{
    int cas;
    scanf("%d", &cas);
    while(cas--)
    {
        scanf("%d %d", &m, &k);
        for(int i = maxi = 1; i <= m; ++i)
        {
            scanf("%d", &a[i]);
            s[i] = s[i - 1] + a[i];
            if(a[i] > a[maxi]) maxi = i;
        }

        le = a[maxi], ri = s[m];
        while(le <= ri)
        {
            mid = (le + ri) >> 1;
            if(divs() <= k) mins = mid, ri = mid - 1;
            else le = mid + 1;
        }

        t = 0;
        memset(d, 0, sizeof(d));
        for(int i = m; i > 0; --i)
        {
            if(t + a[i] > mins)
                d[i] = k--, t = 0;
            if(k >= i) while(i > 0) d[--i] = 1;
            t = t + a[i];
        }

        for(int i = 1; i <= m; ++i)
        {
            printf("%d%c", a[i], i < m ? ' ' : '\n');
            if(d[i]) printf("/ ");
        }
    }
    return 0;
}
 

Before the invention of book-printing, it was very hard to make a copy of a book. All the contents had to be re-written by hand by so called scribers. The scriber had been given a book and after several months he finished its copy. One of the most famous scribers lived in the 15th century and his name was Xaverius Endricus Remius Ontius Xendrianus (Xerox

). Anyway, the work was very annoying and boring. And the only way to speed it up was to hire more scribers.

Once upon a time, there was a theater ensemble that wanted to play famous Antique Tragedies. The scripts of these plays were divided into many books and actors needed more copies of them, of course. So they hired many scribers to make copies of these books. Imagine you have m

 books (numbered ) that may have different number of pages ( ) and you want to make one copy of each of them. Your task is to divide these books among k scribes, . Each book can be assigned to a single scriber only, and every scriber must get a continuous sequence of books. That means, there exists an increasing succession of numbers such that i-th scriber gets a sequence of books with numbers between b_i-1+1 and b_i. The time needed to make a copy of all the books is determined by the scriber who was assigned the most work. Therefore, our goal is to minimize the maximum number of pages assigned to a single scriber. Your task is to find the optimal assignment.

Input 

The input consists of N cases. The first line of the input contains only positive integer N. Then follow the cases. Each case consists of exactly two lines. At the first line, there are two integersm and k, . At the second line, there are integers  separated by spaces. All these values are positive and less than 10000000.

For each case, print exactly one line. The line must contain the input succession divided into exactly k parts such that the maximum sum of a single part should be as small as possible. Use the slash character (`/') to separate the parts. There must be exactly one space character between any two successive numbers and between the number and the slash.

If there is more than one solution, print the one that minimizes the work assigned to the first scriber, then to the second scriber etc. But each scriber must be assigned at least one book.

2
9 3
100 200 300 400 500 600 700 800 900
5 4
100 100 100 100 100

100 200 300 400 500 / 600 700 / 800 900
100 / 100 / 100 / 100 100

Before the invention of book-printing, it was very hard to make a copy of a book. All the contents had to be re-written by hand by so called scribers. The scriber had been given a book and after several months he finished its copy. One of the most famous scribers lived in the 15th century and his name was Xaverius Endricus Remius Ontius Xendrianus (Xerox). Anyway, the work was very annoying and boring. And the only way to speed it up was to hire more scribers.

Once upon a time, there was a theater ensemble that wanted to play famous Antique Tragedies. The scripts of these plays were divided into many books and actors needed more copies of them, of course. So they hired many scribers to make copies of these books. Imagine you have m books (numbered ) that may have different number of pages ( ) and you want to make one copy of each of them. Your task is to divide these books among k scribes, . Each book can be assigned to a single scriber only, and every scriber must get a continuous sequence of books. That means, there exists an increasing succession of numbers such that i-th scriber gets a sequence of books with numbers between b_i-1+1 and b_i. The time needed to make a copy of all the books is determined by the scriber who was assigned the most work. Therefore, our goal is to minimize the maximum number of pages assigned to a single scriber. Your task is to find the optimal assignment.

Input 

The input consists of N cases. The first line of the input contains only positive integer N. Then follow the cases. Each case consists of exactly two lines. At the first line, there are two integersm and k, . At the second line, there are integers  separated by spaces. All these values are positive and less than 10000000.

For each case, print exactly one line. The line must contain the input succession divided into exactly k parts such that the maximum sum of a single part should be as small as possible. Use the slash character (`/') to separate the parts. There must be exactly one space character between any two successive numbers and between the number and the slash.

If there is more than one solution, print the one that minimizes the work assigned to the first scriber, then to the second scriber etc. But each scriber must be assigned at least one book.

2
9 3
100 200 300 400 500 600 700 800 900
5 4
100 100 100 100 100

100 200 300 400 500 / 600 700 / 800 900
100 / 100 / 100 / 100 100