Submission #305108

#	Time	Username	Problem	Language	Result	Execution time	Memory
305108		LucaDantas	Longest beautiful sequence (IZhO17_subsequence)	C++17	40 / 100	520 ms	2944 KiB

subsequence

#include<bits/stdc++.h>
using namespace std;

using pii = pair<int, int>;

#define ff first
#define ss second

#define pb push_back

constexpr int maxn = 4e5+10;

int a[maxn], k[maxn], n;

int dp[maxn], dp_mask[1<<20]; // for the 3rd subtask

int ant[maxn], pos_mask[1<<20];

void print(int ans) {
	printf("%d\n", dp[ans]);
	vector<int> resp;
	while(ans) {
		resp.pb(ans);
		ans = ant[ans];
	}
	reverse(resp.begin(), resp.end());
	for(auto it : resp)
		printf("%d ", it);
	printf("\n");
}

void sub3() {
	for(int i = 1; i <= n; i++) {
		if(a[i] > (1<<9)) assert(0);
		dp[i] = 1;
		for(int mask = 0; mask < (1<<10); mask++)
			if(__builtin_popcount(mask&a[i]) == k[i] && dp[i] <= dp_mask[mask])
				dp[i] = dp_mask[mask]+1, ant[i] = pos_mask[mask];
		if(dp[i] > dp_mask[a[i]])
			dp_mask[a[i]] = dp[i], pos_mask[a[i]] = i;
	}
}

void sub2() {
	for(int i = 1; i <= n; i++) {
		dp[i] = 1;
		for(int j = 1; j < i; j++)
			if(__builtin_popcount(a[j]&a[i]) == k[i] && dp[i] <= dp[j])
				dp[i] = dp[j]+1, ant[i] = j;
	}
}

int main() {
	scanf("%d", &n);
	for(int i = 1; i <= n; i++)
		scanf("%d", &a[i]);
	for(int i = 1; i <= n; i++)
		scanf("%d", &k[i]);
	if(n > 5000) sub3();
	else sub2();
	int ans = 0;
	for(int i = 1; i <= n; i++)
		if(dp[i] >= dp[ans])
			ans = i;
	print(ans);
}

Compilation message (stderr)

subsequence.cpp: In function 'int main()':
subsequence.cpp:54:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
subsequence.cpp:56:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   56 |   scanf("%d", &a[i]);
      |   ~~~~~^~~~~~~~~~~~~
subsequence.cpp:58:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   58 |   scanf("%d", &k[i]);
      |   ~~~~~^~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 0 / 60