神秘无 bitset 做法求证明/证伪

#include <bits/stdc++.h>
using namespace std;
int n,c[40005],ans,que[40005],l,r,sum = 0,Time = 0;
bool Bit[40005],vis[40005],p[40005];
#define max(a,b) (a>b?a:b)
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	cin >> n;
	for(int i = 1;i <= n;++i) cin >> c[i];
	for(int i = 1;i <= n;++i) if(i + c[i] <= n) Bit[i+c[i]] = 1;
	for(int i = n;i >= 1;--i){
		if(!(i & 1)) continue;
		if(Bit[i] == 1) continue;
		for(int j = 1;j <= r;++j) vis[que[j]] = 0,p[c[que[j]]] = 0;
		l = r = 1,que[1] = i,vis[i] = 1,sum = 0;
		while(l <= r){
			int x = que[l++];
			if(p[c[x]] == 0) p[c[x]] = 1,++sum;
			if(x + c[x] <= n && vis[x+c[x]] == 0) vis[x+c[x]] = 1,que[++r] = x + c[x];
			if((x << 1) <= n && vis[(x<<1)] == 0) vis[(x<<1)] = 1,que[++r] = (x << 1);
		}
		ans = max(ans,sum),Time += r;
	}
	cout << ans << " " << Time;
	return 0;
}