【动态规划】Codeforces Round #417 (Div. 2) B. Sagheer, the Hausmeister

#include<cstdio>
#include<algorithm>
using namespace std;
int n,m,left[20],right[20],f[20][2];
char a[20][110];
int main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=n;++i){
scanf("%s",a[i]+1);
}
for(int i=1;i<=n;++i){
left[i]=m+2;
right[i]=1;
for(int j=1;j<=m;++j){
if(a[i][j+1]=='1'){
left[i]=j+1;
break;
}
}
for(int j=m;j>=1;--j){
if(a[i][j+1]=='1'){
right[i]=j+1;
break;
}
}
}
f
[1]=m+1;
for(int i=n-1;i>=0;--i){
f[i][0]=min(f[i+1][0]+(right[i+1]-1)*2+1,f[i+1][1]+m+2);
f[i][1]=min(f[i+1][1]+(m+2-left[i+1])*2+1,f[i+1][0]+m+2);
}
int nn=n+1; left[nn]=m+2; right[nn]=1;
for(int i=n;i>=1;--i){
if(right[i]!=1){
nn=i;
}
}
printf("%d\n",min(f[nn][0]+right[nn]-1,f[nn][1]+m+2-left[nn]));
return 0;
}