二分--CodeForces
You are given an array a with n elements. Each element of a is either 0 or 1.
Let's denote the length of the longest subsegment of consecutive elements in a, consisting of only numbers one, as f(a). You can change no more than k zeroes to ones to maximize f(a).
InputThe first line contains two integers n
The second line contains n integers ai (0 ≤ ai ≤ 1) — the elements of a.
OutputOn the first line print a non-negative integer z — the maximal value of f(a) after no more than kchanges of zeroes to ones.
On the second line print n
If there are multiple answers, you can print any one of them.
Example Input7 1
1 0 0 1 1 0 1
Output
4
1 0 0 1 1 1 1
Input
10 2
1 0 0 1 0 1 0 1 0 1
Output
5
1 0 0 1 1 1 1 1 0 1
這道題題意:給定0.1組成的陣列,可以改變k個0使其為1,問最終可以得到的連續的1的最大長度。
// main.cpp
// temp
//
// Created by Sly on 2017/2/27.
// Copyright © 2017年 Sly. All rights reserved.
//
#include <iostream> //二分
#include <stdio.h>
#include <string.h>
#include <vector>
#define N 100000*3
int t[N];
int a[N];
int n,k;
int Bin(int x) //二分
{
int mid;
int l=1;
int r=x;
while(l<=r)
{
mid=(l+r)>>1;
if(t[x]-t[mid-1]<=k)
r=mid-1;
else l=mid+1;
}
return l;
}
int main()
{
int i;
while(scanf("%d %d",&n,&k)!=EOF)
{
t[0]=0;
for(i=1;i<=n;i++)
{
scanf("%d",&a[i]);
if(!a[i])t[i]=t[i-1]+1;
else t[i]=t[i-1];
}
int ans=0;
int l=0,r=0;
for(i=1;i<=n;i++)
{
int f=Bin(i);
if(i-f+1>ans)
{
ans=i-f+1;
l=f;
r=i;
}
}
printf("%d\n",ans);
for(i=1;i<=n;i++)
{
if(i>=l&&i<=r)
{
printf("1");
if(i!=n)printf(" ");
else printf("\n");
}
else
{
printf("%d",a[i]);
if(i!=n)printf(" ");
else printf("\n");
}
}
}
return 0;
}