Uvalive 7203 at the most twice

title Link:https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_ problem&problem=5215

Test Instructions: Give a number U (1≤u≤1018), ask for a maximum number smaller than u, this number to meet in this number of each number not more than 2 times.

idea:DFS search maintains an array of records of how many times each number has been present.

1 //#include <bits/stdc++.h>2#include <cstring>3#include <cstdio>4#include <string>5#include <iostream>6 using namespacestd;7 Long LongU;8 intnum[ -];9 intans[ -];Ten intmark[ A]; One intLen; A BOOLFind; - voidDfsintCurintlimit) - { the    if(Find)return; -    if(Cur <0) -    { -        BOOLFlag =true; +         for(inti = len-1; I >=0; i--) -        { +            if(flag && ans[i] = =0)Continue; A            Else if(Flag && ans[i]! =0) at            { -printf"%d", Ans[i]); -Flag =false; -            } -            Elseprintf"%d", Ans[i]); -        } inprintf"\ n"); -Find =true; to        return; +    }  -    intup = Limit?num[cur]:9; the     for(inti = up; I >=0; i--) *    { $        if(Mark[i] >=2)Continue;Panax Notoginsengmark[i]++; -Ans[cur] =i; theDFS (cur-1, limit && i = =Up ); +        if(Find)return; Amark[i]--; the    } +    return; -     $ } $ voidSlove (Long Longx) - { -Len =0; the      while(x) -     {Wuyinum[len++] = x%Ten; theX/=Ten; -     } Wumemset (Mark,0,sizeof(Mark)); -DFS (len-1,1); About } $ intMain () - { -   //freopen ("In.txt", "R", stdin); -   //freopen ("OUT.txt", "w", stdout); A      while(~SCANF ("%lld", &U)) +     { theFind =false; - Slove (U); $     } the     return 0; the}

Uvalive 7203 at the most twice