java 使用简单的demo实例告诉你优化算法的强大

for (long i = 1,v = value; i <= v; i++) {
sum += i;
}
return sum;
}

/**
* 累加算法实现<br>
*
* @date 2013-4-16
* @author hongten
*
*/
public class AddArithmetic {

/**
* 循环实现累加方法
* @param value
* @return
*/
private static long cycle(long value) {
long sum = 0;

for (long i = 1,v = value; i <= v; i++) {
sum += i;
}
return sum;
}

/**
* 高斯方法:<code>(n+1)*n/2</code><br>
* you can read more from <a href="http://zhidao.baidu.com/question/411055258.html">Here</a>
* @param value
* @return
*/
private static long gaosi(long value) {
long sum = 0;
sum = (value + 1) * value / 2;
return sum;
}

public static void main(String[] args) {
//清理一下内存，但不一定会执行
System.gc();
// you should change value,then get the different results
long value = 10000000;
long sum = 0;
long start = System.currentTimeMillis();
sum = cycle(value);
long end = System.currentTimeMillis();
System.out.println("使用循环累加方法从[1]累加到["+value+"]用时 ： ["+(end - start) + "]ms,结果："+ sum);
//清理一下内存，但不一定会执行
System.gc();
start = System.currentTimeMillis();
sum = gaosi(value);
end = System.currentTimeMillis();
System.out.println("使用高斯方法从[1]累加到["+value+"]用时 ： ["+(end - start) + "]ms,结果："+ sum);

}

}