再一道区间DP -- P4170 [CQOI2007]涂色

https://www.luogu.org/problemnew/show/P4170

一道简单的区间DP,注意读入

#include <bits/stdc++.h>
#define up(i,l,r) for(int i = (l);i <= (r); i++)
using namespace std;
int f[55][55];
char s[55];
int main()
{
//    freopen("color.in","r",stdin);
    memset(f,0x7F,sizeof(f));
    scanf("%s",s + 1);
    int n = strlen(s + 1);
    up(i,1,n) f[i][i] = 1;
    up(L,1,n - 1)
        for(int i = 1,j = i + L; j <= n;i++,j++)
        {
            if(s[i] == s[j]) f[i][j] = min(f[i + 1][j],f[i][j - 1]);
            else up(k,i,j - 1) f[i][j] = min(f[i][j],f[i][k] + f[k + 1][j]);
        }
    printf("%d",f[1][n]);
    return 0;
}