相似基因

https://www.luogu.org/problemnew/show/P1140

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#include <stack>
#include <cmath>
#define ll long long
using namespace std;

const int MAXN=105,inf=1000000000;
int n,m,cnt,a[MAXN],b[MAXN],f[MAXN][MAXN];
const int tab[5][5]=
{
    {5,-1,-2,-1,-3},
    {-1,5,-3,-2,-4},
    {-2,-3,5,-2,-2},
    {-1,-2,-2,5,-1},
    {-3,-4,-2,-1,0}
};
char c;

void init()
{
	scanf("%d",&n);cnt=1;
	while(cnt<=n){
		c=getchar();
		if(c=='A') a[cnt++]=0;
		if(c=='C') a[cnt++]=1;
		if(c=='G') a[cnt++]=2;
		if(c=='T') a[cnt++]=3;
	}
	scanf("%d",&m);cnt=1;
	while(cnt<=m){
		c=getchar();
		if(c=='A') b[cnt++]=0;
		if(c=='C') b[cnt++]=1;
		if(c=='G') b[cnt++]=2;
		if(c=='T') b[cnt++]=3;
	}
}

int main(){init();
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			f[i][j]=-inf;
	for(int i=1;i<=n;i++) f[i][0]=f[i-1][0]+tab[a[i]][4];
    for(int i=1;i<=m;i++) f[0][i]=f[0][i-1]+tab[b[i]][4];
    for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++){
            f[i][j]=max(f[i][j],f[i][j-1]+tab[b[j]][4]);
            f[i][j]=max(f[i][j],f[i-1][j]+tab[a[i]][4]);
            f[i][j]=max(f[i][j],f[i-1][j-1]+tab[a[i]][b[j]]);
        }
    printf("%d\n",f[n][m]);
	return 0;
}