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Gym 100917J---dir -C(RMQ--ST)

题目链接

http://codeforces.com/gym/100917/problem/D

 

problem description

Famous Berland coder and IT manager Linus Gates announced his next proprietary open-source system "Winux 10.04 LTS"

In this system command "dir -C" prints list of all files in the current catalog in multicolumn mode.

Lets define the multicolumn mode for number of lines l. Assume that filenames are already sorted lexicographically.

  • We split list of filenames into several continuous blocks such as all blocks except for maybe last one consist of l filenames, and last block consists of no more than l filenames, then blocks are printed as columns.
  • Width of each column wi is defined as maximal length of the filename in appropriate block.
  • Columns are separated by 1 × l column of spaces.
  • So, width of the output is calculated as 技术分享, i.e. sum of widths of each column plus number of columns minus one.

Example of multi-column output:


a accd e t
aba b f wtrt
abacaba db k

In the example above width of output is equal to 19.

"dir -C" command selects minimal l, such that width of the output does not exceed width of screen w.

Given information about filename lengths and width of screen, calculate number of lines l printed by "dir -C" command.

Input

First line of the input contains two integers n and w — number of files in the list and width of screen (1 ≤ n ≤ 105, 1 ≤ w ≤ 109).

Second line contains n integers fi — lengths of filenames. i-th of those integers represents length of i-th filename in the lexicographically ordered list (1 ≤ fi ≤ w).

Output

Print one integer — number of lines l, printed by "dir -C" command.

Examples
input
11 20
1 3 7 4 1 2 1 1 1 1 4
output
3

题意:有n个目录名字符串,长度为a[1]~a[n] 屏幕宽为w ,现在要按照已经给的目录循序一列一列的放,每一列放x个,最后一列放<=x个 要求每一列目录名左端对整齐 ,形成一个长方形的块 ,且块与块之间空一格,且不能超过屏幕的宽度,求最小的行数;

思路:先对输入长度处理,用ST算出每个区间的最大值,然后枚举行数x 从1 ~ n;

代码如下:
#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <map>#include <cmath>using namespace std;typedef long long LL;const int MAXN = 1e5+5;int a[MAXN],m[30][MAXN];int n;LL w;int main(){    while(scanf("%d%I64d",&n,&w)!=EOF)    {         memset(m,0,sizeof(m));         for(int i=1;i<=n;i++)         {             scanf("%d",&a[i]);             m[0][i]=a[i];         }         for(int i=1;i<=(int)log(n)/log(2);i++)         {             for(int j=1;j+(1<<i)-1<=n;j++)                m[i][j]=max(m[i-1][j],m[i-1][j+(1<<(i-1))]);         }         for(int i=1;i<=n;i++)         {             int k=(int)log(i);             long long sum=0;             for(int j=0;j<n/i;j++)             {                 sum+=(long long)max(m[k][j*i+1],m[k][i*(j+1)-(1<<k)+1])+1;             }             if(n%i!=0) {                k=(int)log(n%i);                sum+=(long long)max(m[k][n-n%i+1],m[k][n-(1<<k)+1])+1;             }             if(sum-1<=w){                printf("%d\n",i);                break;             }         }    }    return 0;}

 

Gym 100917J---dir -C(RMQ--ST)