Submission #322220

#	Time	Username	Problem	Language	Result	Execution time	Memory
322220		dolphingarlic	Swap (BOI16_swap)	C++14	48 / 100	275 ms	262148 KiB

swap

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

int a[1 << 18];
vector<int> dp[1 << 18][17][2], tmp1, tmp2;

void merge(vector<int> &ret, vector<int> &l, vector<int> &r) {
    for (int i = 0, j = 1; i < l.size(); i += j, j <<= 1) {
        for (int k = i; k < i + j; k++) ret.push_back(l[k]);
        for (int k = i; k < i + j; k++) ret.push_back(r[k]);
    }
}

int main() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", a + i);
    int orig = n;
    while (__builtin_popcount(n + 1) != 1) a[++n] = n;

    for (int node = n; node; node--) {
        for (int i = 0; node >> i; i++) for (int j : {0, 1}) {
            if (!(((node >> i + 1) << 1) + j)) continue;
            int val = a[((node >> i + 1) << 1) + j];

            if (node * 2 > n) dp[node][i][j] = {val};
            else {
                int mn = min({val, a[2 * node], a[2 * node + 1]});
                if (mn == val) {
                    dp[node][i][j] = {val};
                    merge(dp[node][i][j], dp[2 * node][0][0], dp[2 * node + 1][0][1]);
                } else if (mn == a[2 * node]) {
                    dp[node][i][j] = {a[2 * node]};
                    merge(dp[node][i][j], dp[2 * node][i + 1][j], dp[2 * node + 1][0][1]);
                } else {
                    tmp1 = tmp2 = {a[2 * node + 1]};
                    merge(tmp1, dp[2 * node][0][0], dp[2 * node + 1][i + 1][j]);
                    merge(tmp2, dp[2 * node][i + 1][j], dp[2 * node + 1][0][0]);
                    dp[node][i][j] = min(tmp1, tmp2);
                }
            }
        }
    }

    for (int i = 0; i < orig; i++) printf("%d ", dp[1][0][1][i]);
    return 0;
}

Compilation message (stderr)

swap.cpp: In function 'void merge(std::vector<int>&, std::vector<int>&, std::vector<int>&)':
swap.cpp:9:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for (int i = 0, j = 1; i < l.size(); i += j, j <<= 1) {
      |                            ~~^~~~~~~~~~
swap.cpp: In function 'int main()':
swap.cpp:20:46: warning: operation on 'n' may be undefined [-Wsequence-point]
   20 |     while (__builtin_popcount(n + 1) != 1) a[++n] = n;
      |                                              ^~~
swap.cpp:20:46: warning: operation on 'n' may be undefined [-Wsequence-point]
swap.cpp:24:31: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   24 |             if (!(((node >> i + 1) << 1) + j)) continue;
      |                             ~~^~~
swap.cpp:25:37: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |             int val = a[((node >> i + 1) << 1) + j];
      |                                   ~~^~~
swap.cpp:17:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
swap.cpp:18:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   18 |     for (int i = 1; i <= n; i++) scanf("%d", a + i);
      |                                  ~~~~~^~~~~~~~~~~~~

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