最长边截短为：其它两边之和减一

最长边大于其它两边之和的话，就截短为其它两边之和减一的长度：

import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(), b = sc.nextInt(), c = sc.nextInt();
        int sum = a + b + c;
        int A = Math.max(Math.max(a, b), c);
        if(A >= sum - A) System.out.println(2*(sum - A) - 1);
        else System.out.println(sum);
    }
}