CF1463C Busy Robot

https://codeforc.es/contest/1463/problem/C

这是昨晚的cf题，我很难过没能ac，是因为当时的精神状态不好

这个模拟其实不难写，定义两个东西，当前位置pos和目标位置ans就好了，多睡觉吧，睡醒了才聪明啊

ans小于pos就退步，ans大于pos就进步，写了再说，先写了再说

#include<iostream>
#include<cstring>
#include<queue>
using namespace std;
typedef long long ll;
const int maxn = 2e5+111;
pair<ll,ll>ins[maxn],chal[maxn];

int main(){
	int t;
	cin>>t;
	while(t--){
		int n;
		cin>>n;
		for(int i=0;i<n;i++){
			cin>>ins[i].first;
			cin>>ins[i].second;
		}
		ins[n] = make_pair(2e17,2e16);
		ll pos = 0,ans = 0;
		
		ans = ins[0].second;
		chal[0] = make_pair(0,ans);
		
		
		for(int i=1;i<=n;i++){
			ll x = ins[i].first;
			ll y = ins[i].second;
			ll len = ins[i].first - ins[i-1].first;
			
			if(ans > pos){
				pos += len;
				if(pos >= ans) {
					pos = ans;
					ans = y;
				}
			}
			else{
				pos -= len;
				if(pos <= ans){
					pos = ans;
					ans = y;
				}
			}
			chal[i] = make_pair(pos,ans);
		}
	
		ll ddd = 0;
		
		for(int i=0;i<n;i++){
			ll y = ins[i].second;
			if(chal[i].first <= y && y <= chal[i+1].first){
				ddd++;
			}
			else if(chal[i+1].first <= y && y <= chal[i].first){
				ddd++;
			}
		}
		
		cout<<ddd<<endl<<endl;
	}
	return 0;
}