自然数拆分为连续和

转载请注明作者与出处：franciscolv http://www.cnblogs.com/franciscolv/archive/2011/11/20/2255881.html。

package SortSet;

import java.util.HashMap;
import java.util.Map;

/**
 * 9 =2+3+4; 9=4+5; 拆分整数N
 * @author franciscolv 
 */
public class DividedNum {
    private static Map<Integer, Integer> map = new HashMap<Integer, Integer>();

    public static void main(String[] args) {
        getDividedNum(9);
        for (int k : map.keySet()) {
            print(k, map.get(k));
        }
    }

    public static Map<Integer, Integer> getDividedNum(int num) {
        int i = 0;
        int mid = (num + 1) / 2;
        int sum = 0;
        int j = i;
        while (i < mid) {
            if (sum < num) {
                j++;
                sum += j;
            } else if (sum == num) {
                map.put(i, j);
                sum -= i;
                i++;
            } else {
                sum -= i;
                i++;
            }
        }
        return map;
    }

    public static void print(int i, int j) {
        for (int k = i; k < j; k++)
            System.out.print(k + "+");
        System.out.println(j);
    }
}