Submission #1240879

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240879		chikien2009	Lamps (JOI19_lamps)	C++20	100 / 100	31 ms	19784 KiB

lamp

#include <bits/stdc++.h>

using namespace std;

void setup()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int n, f[1000000][3], a[1000000], b[1000000];
char c;

int main()
{
    setup();

    cin >> n;
    for (int i = 0; i < n; ++i)
    {
        cin >> c;
        a[i] = c - '0';
    }
    for (int i = 0; i < n; ++i)
    {
        cin >> c;
        b[i] = c - '0';
    }
    f[0][0] = 1 + (b[0] == 1);
    f[0][1] = 1 + (b[0] == 0);
    f[0][2] = (a[0] != b[0]);
    /* the key is if the color to paint of this cell different from it's requirement
    and the previous cell have not been inversed then this cell have to be inversed*/
    for (int i = 1; i < n; ++i)
    {
        f[i][0] = min({f[i - 1][0] + (b[i] == 1 && b[i - 1] == 0),
                       f[i - 1][1] + 1 + (b[i] == 1 && b[i - 1] == 1),
                       f[i - 1][2] + 1 + (b[i] == 1 && b[i - 1] == a[i - 1])});
        f[i][1] = min({f[i - 1][0] + 1 + (b[i] == 0 && b[i - 1] == 0),
                       f[i - 1][1] + (b[i] == 0 && b[i - 1] == 1),
                       f[i - 1][2] + 1 + (b[i] == 0 && b[i - 1] == a[i - 1])});
        f[i][2] = min({f[i - 1][0] + (a[i] != b[i] && b[i - 1] == 0),
                       f[i - 1][1] + (a[i] != b[i] && b[i - 1] == 1),
                       f[i - 1][2] + (a[i] != b[i] && a[i - 1] == b[i - 1])});
    }
    cout << min({f[n - 1][0], f[n - 1][1], f[n - 1][2]});
    return 0;
}

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