Submission #1116776

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116776		firewater	Lamps (JOI19_lamps)	C++14	100 / 100	68 ms	51788 KiB

lamp

#include<bits/stdc++.h>
#define N 1001000
using namespace std;
int n,ans,a[N],b[N],f[N][5][2];
char s1[N],s2[N];
int main()
 {
 	scanf("%d%s%s",&n,s1+1,s2+1);
	for(int i=1;i<=n;++i)
 		a[i]=s2[i]-'0'+1,b[i]=(s1[i]!=s2[i]);
 	memset(f,127/3,sizeof(f));
    f[0][0][0]=0;
 	for(int i=1;i<=n;++i)
 		for(int j=0;j<=2;++j)
            for(int k=0;k<=1;++k){
                f[i][0][b[i]]=min(f[i][0][b[i]],f[i-1][j][k]+(b[i]&&(b[i]!=k)));
                if(j){
                    f[i][j][k]=min(f[i][j][k],f[i-1][j][k]+(a[i]!=j&&a[i]!=a[i-1]));
                    f[i][j%2+1][!k]=min(f[i][j%2+1][!k],f[i-1][j][k]+(!k)+(a[i]==j&&a[i]==a[i-1]));
                }
                f[i][a[i]][k]=min(f[i][a[i]][k],f[i-1][j][k]+1);
            }
 	ans=f[0][0][1];
 	for(int j=0;j<=2;++j)
        for(int k=0;k<=1;++k)
 	ans=min(ans,f[n][j][k]);
 	printf("%d\n",ans);
 	return 0;
 }

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:8:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |   scanf("%d%s%s",&n,s1+1,s2+1);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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