LeetCode -- Happy Number

public class Solution {
    public bool IsHappy(int n) {
        var digs = n.ToString();
    	var hash = new Dictionary<int, bool>();
    	
    	while(true){
    		int r = 0;
    		for(var i = 0;i < digs.Length; i++){
    			var x = int.Parse(digs[i].ToString());
    			r += x * x;
    		}
    		if(r == 1){
    			return true;
    		}
    		if(!hash.ContainsKey(r)){
    			hash.Add(r, true);
    			digs = r.ToString();
    		}
    		else{
    			return false;
    		}
    	}
	
    }
}

LeetCode -- Happy Number

原文：http://blog.csdn.net/lan_liang/article/details/49108359