AtCoder Beginner Contest 182C

C - To 3

Time Limit: 2 sec / Memory Limit: 1024 MB

Score : 300300 points

Problem Statement

Given is a positive integer N, where none of the digits is 0.Let k be the number of digits in N. We want to make a multiple of 3 by erasing at least 0 and at most k−1 digits from N and concatenating the remaining digits without changing the order.Determine whether it is possible to make a multiple of 3 in this way. If it is possible, find the minimum number of digits that must be erased to make such a number.

Constraints

• 1≤N>ch; dfs(ch,0); if(cnt == 0)//如果全都删了 std::cout