ZOJ 3790 Consecutive Blocks
离散化+暴力
There are N (1 ≤ N ≤ 105) colored blocks (numbered 1 to N from left to right) which are lined up in a row. And the i-th block's color is Ci (1 ≤ Ci ≤ 109). Now you can remove at most K (0 ≤ K ≤ N) blocks, then rearrange the blocks by their index from left to right. Please figure out the length of the largest consecutive blocks with the same color in the new blocks created by doing this.
For example, one sequence is {1 1 1 2 2 3 2 2} and K=1. We can remove the 6-th block, then we will get sequence {1 1 1 2 2 2 2}. The length of the largest consecutive blocks with the same color is 4.
Input
Input will consist of multiple test cases and each case will consist of two lines. For each test case the program has to read the integers N and K, separated by a blank, from the first line. The color of the blocks will be given in the second line of the test case, separated by a blank. The i-th integer means Ci.
Output
Please output the corresponding length of the largest consecutive blocks, one line for one case.
Sample Input
8 1 1 1 1 2 2 3 2 2
Sample Output
4Author: LIN, Xi
Source: ZOJ Monthly, June 2014
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <map>
#include <vector>
using namespace std;
const int maxn=100100;
int n,k,c[maxn],nc,ans;
vector<int> vi[maxn];
void gaoit(int x)
{
int sz=vi[x].size();
if(sz<=ans) return;
int L=0,nowsize=1;
ans=max(ans,nowsize);
for(int i=1;i<sz;i++)
{
nowsize=i-L+1;
while(vi[x][i]-vi[x][L]+1-nowsize>k)
{
L++; nowsize=i-L+1;
}
ans=max(nowsize,ans);
}
}
int main()
{
while(scanf("%d%d",&n,&k)!=EOF)
{
map<int,int> mp;
nc=1;ans=0;
for(int i=0;i<n;i++)
{
int a;
scanf("%d",&a);
if(mp[a]==0) mp[a]=nc++;
c[i]=mp[a];
vi[i+1].clear();
}
for(int i=0;i<n;i++) vi[c[i]].push_back(i);
for(int i=1;i<nc;i++) gaoit(i);
printf("%d\n",ans);
}
return 0;
}