判断回文串递归

int is_palindromes(int i,int j){    if(i>=j) return 1;    if(s[i]!=s[j]) return 0;    if(vis[i][j]==kase) return p[i][j];    vis[i][j]=kase;    p[i][j]=is_palindromes(i+1,j-1);    return p[i][j];}