Submission #104604

#	Time	Username	Problem	Language	Result	Execution time	Memory
104604		antimirage	Lamps (JOI19_lamps)	C++14	0 / 100	1068 ms	21824 KiB

lamp

# include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 5;

int n, dp[N][2], pref[N][2], fl[N];

string a, b;

inline int calc (int l, int r, int type){

      if (type == 0)
            return pref[r][0] - pref[l - 1][0] + (b[l - 1] == b[l] && b[l] == '0');

      return pref[r][1] - pref[l - 1][1] + (b[l - 1] == b[l] && b[l] == '1');
}
main(){

      memset( dp, 0x3f3f3f3f, sizeof(dp) );

      cin >> n >> a >> b;

      a = ' ' + a;
      b = ' ' + b;

      for (int i = 1; i <= n; i++){

            if (a[i] != a[i - 1])
                  fl[i]++;

            fl[i] += fl[i - 1];

            if (b[i] != b[i - 1])
                  pref[i][ b[i] - 48 ] = 1;

            pref[i][0] += pref[i - 1][0];
            pref[i][1] += pref[i - 1][1];
      }
      dp[0][0] = 0;

      for (int i = 1; i <= n; i++){

            if (a[i] == b[i])
                  dp[i][0] = min( dp[i - 1][1], dp[i - 1][0] );

            if (a[i] != b[i])
                  dp[i][1] = min( dp[i - 1][1], dp[i - 1][0] + 1);

            for (int j = i; j >= 1; j--){
                  dp[i][0] = min( dp[i][0], dp[j - 1][0] + calc( j, i, 1 ) + 1 - ( fl[i] == fl[j] && a[i] == '0') );
                  dp[i][0] = min( dp[i][0], dp[j - 1][0] + calc( j, i, 0 ) + 1 - ( fl[i] == fl[j] && a[i] == '1') );

                  dp[i][1] = min( dp[i][1], dp[j - 1][1] + calc( j, i, 0 ) + 1 - ( fl[i] == fl[j] && a[i] == '0') );
                  dp[i][1] = min( dp[i][1], dp[j - 1][1] + calc( j, i, 1 ) + 1 - ( fl[i] == fl[j] && a[i] == '1') );

                  dp[i][1] = min( dp[i][1], dp[j - 1][0] + calc( j, i, 0 ) + 2 - ( fl[i] == fl[j] && a[i] == '1') );
                  dp[i][1] = min( dp[i][1], dp[j - 1][0] + calc( j, i, 1 ) + 2 - ( fl[i] == fl[j] && a[i] == '0') );
            }
      }
      cout << min(dp[n][1], dp[n][0]) << endl;
}

Compilation message (stderr)

lamp.cpp:18:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

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