SPOJ Problem 6219:Edit distance

LCS问题，状态转移方程为f[i][j]=min(f[i-1][j],f[i][j-1],f[i-1][j-1])+1,若a[i]=b[j]则f[i][j]=f[i-1][j-1]

#include<cstdio>
#include<cstring>
#define max(a,b)a>b?a:b
#define INF 1000005
int t,i,j,k,l1,l2,q;
char a[2005],b[2005];
int f[2005][2005];
int min(int a,int b){return a<b?a:b;}
int main(){
    scanf("%d",&t);
    while(t--){
        scanf("%s%s",a,b);
        l1=strlen(a);
        l2=strlen(b);
        for(i=0;i<=l1;i++)
            f[i][0]=i;
        for(i=0;i<=l2;i++)
            f[0][i]=i;
        q=max(l1,l2);
        for (i=1;i<=l1;i++)
            for (j=1;j<=l2;j++){
                f[i][j]=INF;
                if (a[i-1]==b[j-1])f[i][j]=f[i-1][j-1];
                f[i][j]=min(min(min(f[i-1][j],f[i-1][j-1]),f[i][j-1])+1,f[i][j]);
            }
        printf("%d\n",f[l1][l2]);    
    } 
}