算法的特点：

                                正确性、可读性、健壮性、时间效率高和存储量低

大O表示法的规则：    

                                                    1、用常量1取代运行时间中所有常量

                                                    2、在修改运行函数次数中，只保留最高阶

                                                    3、如果最高阶存在且不等于1，则去除这个项目相乘的常数

时间复杂度术语：

                    常数阶：O(1)

                        void testSum(int n){

                                    intsum =0;

                                        sum = (1+ n) * n/2;

                                            printf("testSum:%d",sum);}

                    线性阶：O(n)

                                        void LinearOrder(int n){

                                                            intsum =0;

                                                                for(NSIntegeri =0; i < n; i++) {

                                                                        sum += i;

                                                                        }

                                                                        printf("sum:%d",sum);

                                                                        }

                   对数价：O(Log n)

                            void logarithmicOrder(int n){

                                            intcount =1;

                                              while(count < n) {

                                                count = count *2;    

                                                    printf("********%d",count);

                                                    }

                                            }

                    平方阶：O( 时间复杂度图