JZ-C-41

剑指offer第四十一题：和为s的两个数字：输入一个递增排序的数组和一个数字，在数组中查找两个数，使得它们的和正好等于s。若有多对，输出任意一对即可

 1 //============================================================================
 2 // Name        : JZ-C-41.cpp
 3 // Author      : Laughing_Lz
 4 // Version     :
 5 // Copyright   : All Right Reserved
 6 // Description :和为s的两个数字：输入一个递增排序的数组和一个数字，在数组中查找两个数，使得它们的和正好等于s。若有多对，输出任意一对即可
 7 //============================================================================
 8
 9 #include <iostream>
10 #include <stdio.h>
11 using namespace std;
12
13 bool FindNumbersWithSum(int data[], int length, int sum, int* num1, int* num2) {
14     bool found = false;
15     if (length < 1 || num1 == NULL || num2 == NULL)
16         return found;
17
18     int ahead = length - 1;
19     int behind = 0;
20
21     while (ahead > behind) {
22         long long curSum = data[ahead] + data[behind];
23
24         if (curSum == sum) {
25             *num1 = data[behind];
26             *num2 = data[ahead];
27             found = true;
28             break;
29         } else if (curSum > sum)
30             ahead--;
31         else
32             behind++;
33     }
34
35     return found;
36 }
37
38 // ====================测试代码====================
39 void Test(char* testName, int data[], int length, int sum,
40         bool expectedReturn) {
41     if (testName != NULL)
42         printf("%s begins: ", testName);
43
44     int num1, num2;
45     int result = FindNumbersWithSum(data, length, sum, &num1, &num2);
46     if (result == expectedReturn) {
47         if (result) {
48             if (num1 + num2 == sum)
49                 printf("Passed. \n");
50             else
51                 printf("Failed. \n");
52         } else
53             printf("Passed. \n");
54     } else
55         printf("Failed. \n");
56 }
57
58 // 存在和为s的两个数字，这两个数字位于数组的中间
59 void Test1() {
60     int data[] = { 1, 2, 4, 7, 11, 15 };
61     Test("Test1", data, sizeof(data) / sizeof(int), 15, true);
62 }
63
64 // 存在和为s的两个数字，这两个数字位于数组的两段
65 void Test2() {
66     int data[] = { 1, 2, 4, 7, 11, 16 };
67     Test("Test2", data, sizeof(data) / sizeof(int), 17, true);
68 }
69
70 // 不存在和为s的两个数字
71 void Test3() {
72     int data[] = { 1, 2, 4, 7, 11, 16 };
73     Test("Test3", data, sizeof(data) / sizeof(int), 10, false);
74 }
75
76 // 鲁棒性测试
77 void Test4() {
78     Test("Test4", NULL, 0, 0, false);
79 }
80
81 int main(int argc, char** argv) {
82     Test1();
83     Test2();
84     Test3();
85     Test4();
86
87     return 0;
88 }