Submission #796808

#	Time	Username	Problem	Language	Result	Execution time	Memory
796808		vjudge1	Lamps (JOI19_lamps)	C++17	100 / 100	94 ms	3328 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 inf = 1e9;

//              first 
// memory optimization
//              second 
// 0 - all 0, 
// 1 - all 1
// 2 - no changes, 
//              thrid
// 0 not have xor
// 1 have xor

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

    int n, cr = 1, pr = 0;
    string a, b;
    cin >> n >> a >> b;
    vector < vector < vector < int > > > dp(2, vector < vector < int > > (3, vector < int > (2, inf)));
    dp[pr][2][0] = 0;
    for(int i = 0; i < n; ++ i) {
        dp[cr] = {{inf, inf}, {inf, inf}, {inf, inf}};
        if(a[i] == b[i]) {
            dp[cr][2][0] = min({dp[pr][2][0], dp[pr][2][1], dp[pr][1][0], dp[pr][1][1], dp[pr][0][0], dp[pr][0][1]});
        } else {
            dp[cr][2][1] = min({dp[pr][2][0] + 1, dp[pr][2][1], dp[pr][1][0] + 1, dp[pr][1][1], dp[pr][0][0] + 1, dp[pr][0][1]});
        }
        if(b[i] == '0') {
            dp[cr][0][0] = min({dp[pr][0][0], dp[pr][2][0] + 1, dp[pr][2][1] + 1, 
                                dp[pr][0][1], dp[pr][1][0] + 1, dp[pr][1][1] + 1});

            dp[cr][1][1] = min({dp[pr][1][1], dp[pr][1][0] + 1, dp[pr][2][1] + 1, 
                                              dp[pr][0][1] + 1, dp[pr][2][0] + 2, dp[pr][0][0] + 2});
        } else {
            dp[cr][1][0] = min({dp[pr][1][0], dp[pr][2][0] + 1, dp[pr][2][1] + 1,
                                dp[pr][1][1], dp[pr][0][0] + 1, dp[pr][0][1] + 1});

            dp[cr][0][1] = min({dp[pr][0][1], dp[pr][0][0] + 1, dp[pr][2][1] + 1, 
                                              dp[pr][1][1] + 1, dp[pr][2][0] + 2, dp[pr][1][0] + 2});
        }
        swap(cr, pr);
    }
    cout << min({dp[pr][0][0], dp[pr][0][1], dp[pr][1][0], dp[pr][1][1], dp[pr][2][0], dp[pr][2][1]});
}

Compilation message (stderr)

lamp.cpp:24:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   24 | main() {
      | ^~~~

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