Submission #245603

#	Time	Username	Problem	Language	Result	Execution time	Memory
245603		thecodingwizard	Swap (BOI16_swap)	C++11	68 / 100	685 ms	262144 KiB

swap

#include <bits/stdc++.h>

using namespace std;

const int maxn = 200000;

int n, A[maxn+10];
vector<int> dp[maxn+10][36];

void merge(vector<int> &res, int root, vector<int> &L, vector<int> &R) {
    res.push_back(root);
    int lidx = 0, ridx = 0;
    int cur = 1;
    while (lidx < L.size() || ridx < R.size()) {
        for (int i = 0; i < cur; i++) {
            if (lidx < L.size()) res.push_back(L[lidx++]);
        }
        for (int i = 0; i < cur; i++) {
            if (ridx < R.size()) res.push_back(R[ridx++]);
        }
        cur *= 2;
    }
}

int main() {
    cin.tie(0); ios_base::sync_with_stdio(0);
    cin >> n; for (int i = 1; i <= n; i++) cin >> A[i];
    for (int i = n; i; i--) {
        int l = i*2, r = i*2+1;
        for (int j = 0; j < 36; j++) {
            int idx = i, p = j;
            while (p >= 2) {
                p -= 2;
                idx /= 2;
            }
            if (p == 1) idx *= 2;
            if (idx == 0) continue;

            int cur = A[idx];

            if (l > n && r > n) {
                dp[i][j].push_back(cur);
                continue;
            } else if (r > n) {
                if (A[l] < cur) {
                    dp[i][j].push_back(A[l]);
                    dp[i][j].push_back(cur);
                } else {
                    dp[i][j].push_back(cur);
                    dp[i][j].push_back(A[l]);
                }
                continue;
            }

            int L = A[l], R = A[r];
            // no swap
            if (cur < L && cur < R) {
                merge(dp[i][j], cur, dp[l][0], dp[r][0]);
                continue;
            }

            // swap left
            if (cur > L && L < R) {
                merge(dp[i][j], L, dp[l][j+2], dp[r][0]);
                continue;
            }

            if (R < cur && R < L) {
                // swap right
                merge(dp[i][j], R, dp[l][0], dp[r][j+2]);
                vector<int> tmp;
                // swap both
                merge(tmp, R, dp[l][j+2], dp[r][3]);
                if (tmp < dp[i][j]) {
                    dp[i][j] = tmp;
                }
            }
        }

        if (l <= n) {
            for (int j = 0; j < 36; j++) dp[l][j].clear();
        }
        if (r <= n) {
            for (int j = 0; j < 36; j++) dp[r][j].clear();
        }
    }
    for (int v : dp[1][0]) cout << v << " ";
    cout << "\n";
    return 0;
}

Compilation message (stderr)

swap.cpp: In function 'void merge(std::vector<int>&, int, std::vector<int>&, std::vector<int>&)':
swap.cpp:14:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (lidx < L.size() || ridx < R.size()) {
            ~~~~~^~~~~~~~~~
swap.cpp:14:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (lidx < L.size() || ridx < R.size()) {
                               ~~~~~^~~~~~~~~~
swap.cpp:16:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if (lidx < L.size()) res.push_back(L[lidx++]);
                 ~~~~~^~~~~~~~~~
swap.cpp:19:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if (ridx < R.size()) res.push_back(R[ridx++]);
                 ~~~~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 11 / 11
• Subtask 3: 27 / 27
• Subtask 4: 20 / 20
• Subtask 5: 0 / 32