AC日记——Sagheer, the Hausmeister codeforces 812b

812B - Sagheer, the Hausmeister

思路：

　　搜索；

代码：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define maxn 20
#define maxm 105
#define INF 0x7fffffff

int n,m,deep[maxn][2],num[maxn],ans=INF,k,sum[maxn],cnt;

char map[maxn][maxm];

void dfs(int now,bool st,int val)
{
    if(val>=ans) return;
    if(now==n)
    {
        if(num[now])
        {
            if(st) val+=k-deep[now][0];
            else val+=deep[now][1]-1;
        }
        if(val<ans) ans=val;
        return;
    }
    if(sum[now]==cnt)
    {
        if(num[now])
        {
            if(st) val+=k-deep[now][0];
            else val+=deep[now][1]-1;
        }
        if(val<ans) ans=val;
        return;
    }
    if(num[now])
    {
        if(st) dfs(now+1,st^1,val+k),dfs(now+1,st,val+(k-deep[now][0])*2+1);
        else dfs(now+1,st,val+deep[now][1]*2-1),dfs(now+1,st^1,val+k);
    }
    else dfs(now+1,st,val+1),dfs(now+1,st^1,val+k);
}

int main()
{
    scanf("%d%d",&n,&m);k=m+2;
    for(int i=1,i_=n;i<=n;i++,i_=n-i+1)
    {
        scanf("%s",map[i]+1);
        for(int j=1;j<=m+2;j++)
        {
            if(map[i][j]=='1'&&(!deep[i_][0])) deep[i_][0]=j;
            if(map[i][j]=='1') deep[i_][1]=j,num[i_]++;
        }
    }
    for(int i=1;i<=n;i++) sum[i]=sum[i-1]+num[i],cnt+=num[i];
    dfs(1,false,0),printf("%d
",ans);
    return 0;
}