2014人人网校园招聘技术笔试

此题目及解答来源于博友：http://blog.csdn.net/wanglongfei_hust/article/details/11865037

考虑到空间时间复杂度为O（n）！

#include <iostream>using namespace std;int hash_table[100];bool judge(int *a, int len, int x){memset(hash_table, 0, sizeof(hash_table));for (int i=0; i<len; ++i){hash_table[x - a[i]] = 1;}for (int i=0; i<len; ++i){if (hash_table[i] == 1){return true;}}return false;}int main(){int len = 10;int a[10] = {1, 3, 5, 7, 9, 4, 2, 8, 10, 6};int x = 19;if (judge(a, len, x)){cout<<"Yes"<<endl;}else{cout<<"No"<<endl;}return 0;}

#include <iostream>using namespace std;int find(int *a, int n){int t = a[0];int count = 0;for (int i=0; i<n; ++i){if (count == 0){t = a[i];count = 1;continue;}else{if (a[i] == t){count++;}else{count--;}}}return t;}int main(){int n = 10;int a[10] = {1, 2, 2, 2, 2, 4, 3, 3, 2, 6};cout<<find(a, n)<<endl;return 0;}