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]);    } 
}