Submission #1214646

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214646		CrabCNH	Lamps (JOI19_lamps)	C++20	100 / 100	44 ms	39512 KiB

lamp

#include <bits/stdc++.h>

#define task     "BriantheCrab"

#define int    long long
#define pii    pair <int, int>
#define fi     first
#define se     second
#define szf    sizeof
#define sz(s)  (int)((s).size())
#define all(v) (v).begin(), (v).end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using namespace std;

template <class T> void minimize (T &t, T f) {if (t > f) t = f;}
template <class T> void maximize (T &t, T f) {if (t < f) t = f;}

const int maxN = 1e6 + 10;
const int inf = 1e9 + 7;

int n, a[maxN], b[maxN];
int dp[maxN][3];

void solve () {
    cin >> n;
    for (int i = 1; i <= n; i ++) {
        char c;
        cin >> c;
        a[i] = (c == '1');
    }
    for (int i = 1; i <= n; i ++) {
        char c;
        cin >> c;
        b[i] = (c == '1');
        dp[i][0] = dp[i][1] = dp[i][2] = inf;
    }
    dp[1][0] = 1 + ((0 ^ b[1]) == 1);
    dp[1][1] = 1 + ((1 ^ b[1]) == 1);
    dp[1][2] = ((a[1] ^ b[1]) == 1);
    for (int i = 2; i <= n; i ++) {
        minimize (dp[i][0], dp[i - 1][0] + ((0 ^ b[i]) == 1 && (0 ^ b[i - 1]) == 0));
        minimize (dp[i][0], dp[i - 1][1] + ((0 ^ b[i]) == 1 && (1 ^ b[i - 1]) == 0) + 1);
        minimize (dp[i][0], dp[i - 1][2] + ((0 ^ b[i]) == 1 && (a[i - 1] ^ b[i - 1]) == 0) + 1);
        minimize (dp[i][1], dp[i - 1][0] + ((1 ^ b[i]) == 1 && (0 ^ b[i - 1]) == 0) + 1);
        minimize (dp[i][1], dp[i - 1][1] + ((1 ^ b[i]) == 1 && (1 ^ b[i - 1]) == 0));
        minimize (dp[i][1], dp[i - 1][2] + ((1 ^ b[i]) == 1 && (a[i - 1] ^ b[i - 1]) == 0) + 1);
        minimize (dp[i][2], dp[i - 1][0] + ((a[i] ^ b[i]) == 1 && (0 ^ b[i - 1]) == 0));
        minimize (dp[i][2], dp[i - 1][1] + ((a[i] ^ b[i]) == 1 && (1 ^ b[i - 1]) == 0));
        minimize (dp[i][2], dp[i - 1][2] + ((a[i] ^ b[i]) == 1 && (a[i - 1] ^ b[i - 1]) == 0));
    }
    cout << min ({dp[n][0], dp[n][1], dp[n][2]});
    return;
}

signed main () {
    cin.tie (nullptr) -> sync_with_stdio (false);
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    int t = 1;
    //cin >> t;
    while (t --) {
        solve ();
    } 
    return 0;
}
// thfv

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:62:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:63:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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