codeforce660C

题目链接：http://codeforces.com/problemset/problem/660/C

题目大意：给你一个由1 和 0组成的数组， 最多改变k次，0－>1, 1—>0， 问改变后连续是 1 的长度最大是多少， 并输出改变后的数组

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#include <cmath>
#include <set>
#include <map>
#include <vector>
#define N  300010
using namespace std;

int a[N], b[N];//b[i] 表示i 以前的0的个数
int main()
{
    int n, k;
    scanf("%d %d", &n, &k);
    b[0] = 0;
    for(int i = 1; i <= n; i++)
    {
        scanf("%d", a + i);
        b[i] = b[i - 1] + 1 - a[i];
    }      
    int ii = 0, jj = 0, max = 0;//max记录连续1最长的长度，ii和jj记录起点和终点
    if(b[n] <= k)
        ii = 1, jj = n, max = n;  
    for(int i = 1; i <= n; i++)
    {
        if(b[n] >= b[i - 1] + k + 1){
            int pos = upper_bound(b + 1, b + n + 1, b[i - 1] + k) - b;
            if(pos - i > max){
                max = pos - i;
                ii = i ;
                jj = pos - 1;
            } 
        }        
        if(b[n] == b[i - 1] + k)
        {
            if(n - i  + 1 > max)
            {
                max = n - i + 1;
                ii = i, jj = n;
            }
            break;
        }       
    }
    printf("%d
", max);
    for(int i = 1; i <= n; i++)
    {
        if(i >= ii && i <= jj){
            if(i != n )
                printf("1 ");
            else
                printf("1
");
        }
        else{
            if(i != n )
                printf("%d ", a[i]);
            else
                printf("%d
", a[i]);
        }
    }
    return 0;
}