RT 求优化时间复杂度

#include <bits/stdc++.h>
using namespace std;
struct node{
	bool v; int tim; 
};
inline int read()
{
	int x = 0, tmp = 1; char ch = getchar();
	while (!isdigit(ch))
	{
		if (ch == '-') tmp = -1;
		ch = getchar();
	}
	while (isdigit(ch)) {x = (x << 1) + (x << 3) + (ch ^ 48); ch = getchar();}
	return x * tmp;
}int t, k, x, cnt;
map<int, node> a;
int main()
{
	int n = read();
	while (n--)
	{
		t = read(), k = read(); cnt = 0;
		for (int i = 1; i <= k; i++) {x = read(); a[x] = {1, t};}
		for (auto kv:a) 
		{
			if (kv.second.tim > t - 86400 && kv.second.v) cnt++;
			else a[kv.first] = {0, kv.second.tim};
		}printf("%d\n", cnt);
	}
	return 0;
}