Submission #126425

#	Time	Username	Problem	Language	Result	Execution time	Memory
126425		TadijaSebez	Lamps (JOI19_lamps)	C++11	100 / 100	452 ms	43644 KiB

lamp

#include <bits/stdc++.h>
using namespace std;
const int N=1000050;
const int inf=1e9+7;
int dp[N][2][5];
char a[N],b[N];
int main()
{
	int n;
	scanf("%i %s %s",&n,a+1,b+1);
	for(int i=0;i<2;i++) for(int j=0;j<5;j++) dp[0][i][j]=inf;
	dp[0][0][0]=0;
	for(int i=1;i<=n;i++)
	{
        for(int j=0;j<2;j++)
        {
			for(int k=0;k<5;k++)
			{
				int mask=min(k,3)+j*4;
				int now=a[i]-'0';
				if(k>0 && (k&1)) now=0;
				else if(k>0) now=1;
				if(j) now^=1;
				dp[i][j][k]=inf;
				if(now==b[i]-'0')
				{
					for(int j2=0;j2<2;j2++)
					{
						for(int k2=0;k2<5;k2++)
						{
							if(k>=3 && k2>=3 && k!=k2) continue;
							int mask2=min(k2,3)+j2*4;
							int dif=__builtin_popcount(mask^(mask&mask2));
							dp[i][j][k]=min(dp[i][j][k],dp[i-1][j2][k2]+dif);
						}
					}
				}
			}
        }
	}
	int ans=inf;
	for(int j=0;j<2;j++) for(int k=0;k<5;k++) ans=min(ans,dp[n][j][k]);
	printf("%i\n",ans);
	return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i %s %s",&n,a+1,b+1);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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