Submission #823420

#	Time	Username	Problem	Language	Result	Execution time	Memory
823420		yanndev	Lamps (JOI19_lamps)	C++17	100 / 100	167 ms	31700 KiB

lamp

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

const int INF = 1e9;
const int MX = (int)1e6 + 42;
int dp[MX][3][2];

void solve(int tcId) {
    int n;
    cin >> n;
    vector<int> a (n + 1, 0);
    vector<int> b (n + 1, 0);

    for (int i = 1; i <= n; i++) {
        char v;
        cin >> v;
        a[i] = v - '0';
    }

    for (int i = 1; i <= n; i++) {
        char v;
        cin >> v;
        b[i] = v - '0';
    }

    for (int i = 0; i <= n; i++)
        for (int j = 0; j < 3; j++)
            for (int k = 0; k < 2; k++)
                dp[i][j][k] = INF;
    
    dp[0][2][0] = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < 3; j++) {
            for (int k = 0; k < 2; k++) {
                for (int pJ = 0; pJ < 3; pJ++) {
                    for (int pk = 0; pk < 2; pk++) {
                        if (dp[i - 1][pJ][pk] == INF) continue;
                        int cnt = 0;
                        if (pJ != j && j != 2)
                            cnt++;
                        if (k != pk && k != 0)
                            cnt++;
                        int v = a[i];
                        if (j == 0) v = 0;
                        else if (j == 1) v = 1;
                        if (k) v ^= 1;
                        if (v == b[i])
                            dp[i][j][k] = min(dp[i][j][k], dp[i - 1][pJ][pk] + cnt);
                    }
                }
            }
        }
    }

    int ans = 1e9;
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 2; j++)
            ans = min(ans, dp[n][i][j]);
    cout << ans << '\n';
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    solve(42);
}

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 4 / 4
• Subtask 4: 49 / 49