Submission #1272831

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272831		icebear	Lamps (JOI19_lamps)	C++20	100 / 100	34 ms	14080 KiB

lamp

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

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const ll INF = 1e18 + 27092008;
const int N = 1e6 + 5;
int n, f[N][3];
string A, B;

void init(void) {
    cin >> n >> A >> B;
    A = " " + A;
    B = " " + B;
}

void process(void) {
    memset(f, 0x3f, sizeof f);
    // 0 : off, 1 : on, 2 : none
    f[0][2] = 0;
    REP(i, n) REP(j, 3) if (f[i][j] != inf) {
        bool toggle = false;
        if (i > 0) {
            int cur = (j == 2 ? A[i] - '0' : j);
            toggle = (cur != B[i] - '0');
        }

        REP(k, 3) {
            int nxt = (k == 2 ? A[i + 1] - '0' : k);
            int tar = B[i + 1] - '0';
            if (k != j && max(k, j) != 2) continue;
            minimize(f[i + 1][k], f[i][j] + (j == 2 && k < 2) + (toggle == false && nxt != tar));
        }
    }
    cout << min({f[n][0], f[n][1], f[n][2]});
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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