Title: seeking 1 + 2 + 3 + ... + n, requires multiplication and division can not be used, for, while, if, else, switch, case and keywords such as conditional statement (A B:? C).
Ideas:
1. use of logic required to achieve short-circuit characteristic and the termination of recursion.
2. When n == 0 time, (n> 0) && ( (sum + = Sum_Solution (n-1))> 0) is performed only in front of the judgment is false, and then directly returns 0;
3. When n> 0 performing sum + = Sum_Solution (n-1 ), to achieve the recursive computation Sum_Solution (n)
public class Solution {
public static void main(String[] args) {
Solution solution = new Solution();
System.err.println(solution.Sum_Solution(10));
}
public int Sum_Solution(int n) {
int sum = n;
boolean ans = (n>0)&&((sum+=Sum_Solution(n-1))>0);
return sum;
}
}
