CodeForces 761C 【DP】

总结：能这么DP就这么写！

多练位运算标记。

#include<bits/stdc++.h>
using namespace::std;

const int N=55;
const int INF=0x3f3f3f3f;

int n, m, dp
[2][2][2];
char s

;

bool isdigit(char ch)
{
if(ch>='0' && ch<='9')
return true;
return false;
}

bool isletter(char ch)
{
if(ch>='a' && ch<='z')
return true;
return false;
}

bool issymbols(char ch)
{
if(ch=='*' || ch == '&' || ch == '#')
return true;
return false;
}

int solve(int pos, bool digit, bool letter, bool symbols)
{
if(pos==n)
{
if(digit && letter && symbols)
return 0;
return INF;
}
if(dp[pos][digit][letter][symbols] != -1)
return dp[pos][digit][letter][symbols];
int ans=INF;
for(int j=0; j<m; j++)
{
int cost = min(j, m-j);
if(isdigit(s[pos][j]))
ans = min(ans, cost+ solve(pos+1, 1, letter, symbols));
else if(isletter(s[pos][j]))
ans = min(ans, cost+ solve(pos+1, digit, 1, symbols));
else if(issymbols(s[pos][j]))
ans = min(ans, cost+ solve(pos+1, digit, letter, 1));
}
return dp[pos][digit][letter][symbols]=ans;
}

int main()
{
scanf("%d%d",&n,&m);
for(int i=0; i<n; i++)
scanf("%s",s[i]);
memset(dp, -1, sizeof(dp));
printf("%d\n",solve(0,0,0,0));
return 0;
}