CSU 1411: Longest Consecutive Ones

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关键是通过预处理,使每个区间内的1移动到一起的最少步骤可以在O(1)时间算出来....

Description

Input

Output

Sample Input

3
11101 0
110101001011 3
0000000 1000000000

Sample Output

3
4
0

HINT

Source

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long int LL;
const int maxn=100100;

LL pos[maxn],sum[maxn],K;
int cnt;
char str[maxn];

bool ck(int l,int r)
{
    int mid=(l+r)/2;
    LL temp=0;
    int num=mid-l;
    temp+=pos[mid]*num-num*(num+1)/2-sum[mid-1]+sum[l-1];
    num=r-mid;
    temp+=sum[r]-sum[mid]-num*(num+1)/2-pos[mid]*num;
    if(temp>K)
        return false;
    return true;
}

int main()
{
    int T_T;
    scanf("%d",&T_T);
    while(T_T--)
    {
        scanf("%s",str+1);
        scanf("%I64d",&K);
        int len=strlen(str+1);
        cnt=1;
        for(int i=1;i<=len;i++)
        {
            if(str[i]==‘1‘)
            {
                pos[cnt]=i;
                sum[cnt]=pos[cnt]+sum[cnt-1];
                cnt++;
            }
        }
        cnt--;
        int i=1,ans=0,maxn=1;
        while(true)
        {
            int j=i+maxn-1;
            if(j>cnt) break;
            if(ck(i,j))
            {
               ans=maxn; maxn++;
            }
            else i++;
        }
        printf("%d\n",ans);
    }
    return 0;
}

CSU 1411: Longest Consecutive Ones,码迷,mamicode.com

CSU 1411: Longest Consecutive Ones

标签：des   style   http   color   os   io   

原文地址：http://blog.csdn.net/ck_boss/article/details/24600353