AcWing 1855. 愤怒的奶牛（枚举+暴力）

Posted 2022-02-16 MangataTS

题目链接

https://www.acwing.com/problem/content/1857/

思路

直接模拟每个点都是爆炸点，然后向左向右模拟即可，详情请看代码

代码

#include<bits/stdc++.h>
using namespace std;
//----------------自定义部分----------------
#define ll long long
#define mod 1000000007
#define endl "\\n"
#define PII pair<int,int>

int dx[4]=0,-1,0,1,dy[4]=-1,0,1,0;

ll ksm(ll a,ll b) 
	ll ans = 1;
	for(;b;b>>=1LL) 
		if(b & 1) ans = ans * a % mod;
		a = a * a % mod;
	
	return ans;


ll lowbit(ll x)return -x & x;

const int N = 2e6+10;
//----------------自定义部分----------------
int n,m,q,a[N],d[N];

int slove(int i)
	int l = i,lenl = 1;
	while(l - 1 > 0) //找左边的
		bool fg = false;
		int loc = l - 1;
		while(loc > 0 && a[l] - a[loc] <= lenl) //将len1这个半径范围内的元素全部覆盖
			loc--,fg = true;
		loc++;
		if(fg) lenl++,l = loc;//如果有覆盖操作
		else break;
	

	int r = i,lenr = 1;
	while(r  + 1 <= n) //找到右边的边界处
		bool fg = false;
		int loc = r + 1;
		while(loc <= n && a[loc] - a[r] <= lenr) //将len2这个半径范围内的元素全部覆盖
			loc++,fg = true;
		loc--;
		if(fg) lenr++,r = loc;//如果有覆盖操作
		else break;
	
	return r-l+1;


int main()

	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	std::cout.tie(nullptr);

	cin>>n;
	for(int i = 1;i <= n; ++i) 
		cin>>a[i];
	
	sort(a+1,a+1+n);
	int ans = 1;
	for(int i = 1;i <= n; ++i) 
		int res = slove(i);
//		cout<<"i = "<<i<<" len = "<<res<<endl;
		ans = max(ans,res);
	
	cout<<ans<<endl;

	return 0;