Submission #1281408

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281408		vuquangsang	Lamps (JOI19_lamps)	C++20	100 / 100	41 ms	14144 KiB

lamp

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

const int N = 1e6 + 2;
const int inf = 1e9 + 2;

int n; string a, b;
int dp[N][3];
void solve()
{
    cin >> n >> a >> b;
    a = ' ' + a;
    b = ' ' + b;

    dp[0][0] = dp[0][1] = inf;
    dp[0][2] = 0;

    for(int i = 1; i <= n; i++) {
        bool tar = b[i] - '0';

        for(int j : {0, 1, 2}) dp[i][j] = inf;

        for(int j : {0, 1, 2}) if(dp[i - 1][j] != inf) {
            bool tog = 0;

            if(i > 1) {
                int cur = (j == 2 ? a[i - 1] - '0' : j);
                tog = (cur != (b[i - 1] - '0'));
            }

            for(int k : {0, 1, 2}) {
                if(j != k && max(j, k) < 2) continue;

                int cur = k;
                if(cur == 2) cur = a[i] - '0';
                dp[i][k] = min({dp[i][k], dp[i - 1][j] + (j == 2 && k < 2) + (!tog && cur != tar)});
            }
        }
    }
    cout << min({dp[n][0], dp[n][1], dp[n][2]});
}

main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    #define TASK "lamps"
    if(fopen(TASK".INP", "r")) {
        freopen(TASK".INP", "r", stdin);
        freopen(TASK".OUT", "w", stdout);
    }

    solve();

    cerr << "\nTime" << 0.001 * clock() << "s "; return 0;


}

Compilation message (stderr)

lamp.cpp:43:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   43 | main()
      | ^~~~
lamp.cpp: In function 'int main()':
lamp.cpp:49:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:50:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         freopen(TASK".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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