Submission #792623

#	Time	Username	Problem	Language	Result	Execution time	Memory
792623		vjudge1	Lamps (JOI19_lamps)	C++17	4 / 100	30 ms	67140 KiB

lamp

#ifdef Home
#define _GLIBCXX_DEBUG
#endif // Home

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 2022;

string a, b;
int dp[N][N][4];

// 0 don't touched
// 1 turn off all
// 2 turn on  all
// 3 toggle   all

int change(int pr, int cr) {
    return cr == 3 ? 3 - pr : (cr ? cr : pr);
}

int recur(int l, int r, int sts) {
    int &ans = dp[l][r][sts];
    if(ans != -1) {
        return ans;
    }
    if(l + 1 == r) {
        if(sts == 0) {
            return ans = (a[l] != b[l]);
        } 
        if(sts == 1) {
            return ans = ('0' != b[l]);
        } 
        if(sts == 2) {
            return ans = ('1' != b[l]);
        }
        return ans = (a[l] == b[l]);
    }
    ans = r - l;
    for(int m = l + 1; m < r; ++ m) {
        int ansl = recur(l, m, sts);
        for(int nwsts = 1; nwsts < 4; ++ nwsts) {
            ansl = min(ansl, recur(l, m, change(sts, nwsts)) + 1);
        }
        int ansr = recur(m, r, sts);
        for(int nwsts = 1; nwsts < 4; ++ nwsts) {
            ansr = min(ansr, recur(m, r, change(sts, nwsts)) + 1);
        }
        ans = min(ans, ansl + ansr);
    }
    return ans;
}

main() {
#ifdef Home
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif // Home
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    memset(dp, -1, sizeof dp);
    
    int n;
    cin >> n >> a >> b;
    bool ok = a[0] == '0';
    int ans = a[0] != b[0];
    for(int i = 1; i < a.size(); ++ i) {
        ok &= a[i] == '0';
        ans += (b[i] == '1' && b[i - 1] == '0'); 
    }
    if(ok) {
        cout << ans;
        return 0;
    }
    cout << min( {
    recur(0, n, 0),
    recur(0, n, 1) + 1,
    recur(0, n, 2) + 1,
    recur(0, n, 3) + 1} );
}

Compilation message (stderr)

lamp.cpp:58:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   58 | main() {
      | ^~~~
lamp.cpp: In function 'int main()':
lamp.cpp:72:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |     for(int i = 1; i < a.size(); ++ i) {
      |                    ~~^~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 4 / 4
• Subtask 4: 0 / 49