Submission #893013

#	Time	Username	Problem	Language	Result	Execution time	Memory
893013		NoLove	Longest beautiful sequence (IZhO17_subsequence)	C++14	23 / 100	6056 ms	4444 KiB

subsequence

/**
 *    author : Lăng Trọng Đạt
 *    created: 25-12-2023 
**/
#include <bits/stdc++.h>
using namespace std;
#ifndef LANG_DAT
#define db(...) ;
#endif // LANG_DAT
#define int int64_t
#define mp make_pair
#define f first
#define s second
#define pb push_back
#define all(v) (v).begin(), (v).end()
using pii = pair<int, int>;

const int MAXN = 1e5 + 5;
const int BB = 8;
int g[MAXN], k[MAXN], dp[MAXN], p[MAXN];
int bc[1 << BB][1 << BB];
// pii dp1[1 << 9]; // dp1[i][x]: LBS ending in x
int n, res;
int last = 0;

void sub1() {
    for (int i = 0; i < n; i++) {
        dp[i] = 1;
        p[i] = i;
    }
    for (int i = 1; i < n; i++) {
        for (int j = 0; j < i; j++) {
            if (__builtin_popcount(g[i] & g[j]) == k[i] && dp[j] + 1 > dp[i]) {
                // db(i, j, __builtin_popcount(g[i] & g[j]), k[i])
                dp[i] = dp[j] + 1;
                p[i] = j;
            }
        }
        if (dp[i] > dp[last]) {
            last = i;
        }
    }
    res = dp[last];
}
void sub3() {
    // memset(dp1, -1, sizeof(dp1));
    vector<pii> dp1(1 << BB, {-1, -1});
    for (int i = 0; i < n; i++) {
        // dp1[g[i]].f = 1;
        // dp1[g[i]].s = -1;
        p[i] = i;
    }
    // for (int i = 0; i< n; i++) {
    //     if (dp1[g[i]].s == -1)
    //         dp1[g[i]].s = i;
    // }
    for (int i = 0; i < n; i++) {
        bool id = i & 1;
        if (dp1[g[i]].f == -1) {
            dp1[g[i]] = {1, i};
        }
        for (int j = 0; j < (1 << 8); j++) {
            if (bc[g[i]][j] == k[i] && dp1[j].f + 1 > dp1[g[i]].f && dp1[j].f != -1) {
                // db(g[i], j, dp1[j], dp1[g[i]].f)
                dp1[g[i]].f = dp1[j].f + 1;
                p[i] = dp1[j].s;
                dp1[g[i]].s = i;
            }
        }
        if (dp1[g[i]].f > dp1[g[last]].f) {
            // db(i, g[i], dp1[g[i]].f)
            last = i;
        }
    }
    db(dp1[g[4993]], p[4993], g[4993], k[4993])
    res = dp1[g[last]].f;
}
const int B = 8;
struct State {
	int len, end;
};
void sub3_ans() {

	// preprocess:
	// bc[i][j] = bit_count(i & j)
	vector<vector<int>> bc(1 << B, vector<int>(1 << B));
	for (int i = 0; i < (1 << B); i++) {
		for (int j = 0; j < (1 << B); j++) {
			bc[i][j] = __builtin_popcount(i & j);
		}
	}

	int n;
	cin >> n;
	vector<int> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];
	vector<int> k(n);
	for (int i = 0; i < n; i++) cin >> k[i];
	int ans = 1;
	// best_i: most optimal index to end on
	int best_i = 0;
	vector<int> prv(n);               // prv[i]: best index to include before i
	iota(prv.begin(), prv.end(), 0);  // prv[i] = i

	vector<State> dp1(1 << B, State{-1, -1});
	for (int i = 0; i < n; i++) {
		if (dp1[a[i]].len == -1) {
			dp1[a[i]].len = 1;
			dp1[a[i]].end = i;
		}
		for (int j = 0; j < (1 << B); j++) {
			if (bc[j][a[i]] == k[i] && dp1[j].len + 1 > dp1[a[i]].len) {
				dp1[a[i]].len = dp1[j].len + 1;
				dp1[a[i]].end = i;
				prv[i] = dp1[j].end;
			}
		}
		if (dp1[a[i]].len > ans) {
			ans = dp1[a[i]].len;
			best_i = i;
		}
	}

	cout << ans << endl;

	vector<int> res;
	while (prv[best_i] != best_i) {
		res.push_back(best_i);
		best_i = prv[best_i];
	}
	res.push_back(best_i);
	reverse(res.begin(), res.end());
	for (int x : res) { cout << x + 1 << " "; }
}
int32_t main() {
    cin.tie(0)->sync_with_stdio(0);
    if (fopen("hi.inp", "r")) {
        freopen("hi.inp", "r", stdin);
       freopen("hi2.out", "w", stdout);
    } 

    // preprocess
    if (n <= 5000) {
    for (int i = 1; i < (1 << B); i++)
        for (int j = 1; j < (1 << B); j++)
            bc[i][j] = __builtin_popcount(i & j);
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        std::cin >> g[i];
    }    
    for (int i = 0; i < n; i++) {
        std::cin >> k[i];
    }    

        sub1();
    vector<int> ans = {last};
    while (last != p[last]) {
        // db(last, p[last])
        last = p[last];
        ans.pb(last);
    }
    cout << ans.size() << "\n";
    // cout << ans.size() << "\n";
    reverse(all(ans));
    for (int i : ans) {
        cout << i + 1 << " ";
    }
    } else {
        sub3_ans();
    }
    // db(last)
    // for (int i = (int)ans.size() - 1; i >= 0; i--) {
    // }
    // for (int i = 1; i < ans.size(); i++) {
    //     if (__builtin_popcount(g[ans[i]] & g[ans[i - 1]]) != k[ans[i]]) {
    //         db(ans[i], g[ans[i]], g[ans[i] - 1], __builtin_popcount(g[ans[i]] & g[ans[i - 1]]), k[i])
    //     }
    // }
    // db(ans.size(), res)
}

Compilation message (stderr)

subsequence.cpp: In function 'void sub3()':
subsequence.cpp:58:14: warning: unused variable 'id' [-Wunused-variable]
   58 |         bool id = i & 1;
      |              ^~
subsequence.cpp: In function 'int32_t main()':
subsequence.cpp:138:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |         freopen("hi.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
subsequence.cpp:139:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |        freopen("hi2.out", "w", stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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