#include <iostream>
using namespace std;
int main() {
    int arr[3][2] = {{1, 2}, {3, 4}, {5, 6}};
    int brr[2][3] = {0};
    for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 2; j++) {
            brr[j][i] = arr[i][j];
        }
    }
    for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 3; j++) {
            cout << brr[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}

回文数英语单词：isPlalindrome

回文数判定程序

#include <iostream>
#include <string>
using namespace std;
int main(){
    int len;
    string huiwenshu;
    cin >> huiwenshu;
    len = huiwenshu.size();
    bool realy = true;
    for(int i = 0;i < len / 2;i++){
        if(huiwenshu[i] != huiwenshu[len - i - 1]){
            realy = false;
            break;
        }
    }
    if(realy){
        cout << "Yes";
    }
    else cout << "No";
    return 0;
}

函数思维

#include <iostream>
#include <string>
using namespace std;
bool isPlalindrome(string s){
    int len = s.size();
    for(int i = 0;i < len;i++){
        if(s[i] != s[len - 1 - i]){
            return false;
        }
    }
    return true;
}
int main(){
    string s;
    cin >> s;
    if(isPlalindrome){
        cout << "Yes";
    }
    else cout << "No";
    return 0;
}

求字符串第一个仅出现一次的字母

#include <iostream>
#include <string>
using namespace std;
int main(){
    int t[256];
    string s;
    int i;
    cin >> s;
    for(i = 0;i < 256;i++){
        t[i] = 0;
    }
    for(i = 0;i < s.length();i++){
        t[s[i]]++;
    }
    for(i = 0;i < s.length();i++){
        if(t[s[i]] == 1){
            cout << s[i] << endl;
            return 0;
        }
    }
    cout << "no" << endl;
    return 0;
}

排序算法

归并排序

给定两个有序数列，合并成一个升序数列

#include <iostream>
using namespace std;
int main(){
    const int SIZE = 100;
    int na,nb,a[SIZE],b[SIZE],i,j,k;
    cin >> na;
    for(i = 1;i <= na;i++){
        cin >> a[i];
    }
    cin >> nb;
    for(i = 1;i <= nb;i++){
        cin >> b[i];
    }
    i = 1;
    j = 1;
    while((i <= na) && (j <= nb)){
        if(a[i] <= b[j]){
            cout << a[i] << " ";
        }
        else{
            cout << b[j] << " ";
            j++;
        }
    }
    if(i <= na){
        for(k = i;k <= na;k++){
            cout << a[k] << " ";
        }
    }
    if(j <= nb){
        for(k = j;k <= nb;k++){
            cout << b[k] << " ";
        }
    }
    return 0;
}

二分查找法

#include <iostream>
using namespace std;
const int SIZE = 105;
int arr[SIZE] = {0,11,22,33,44,55,66,77,88,99};
int binary_search(int x){
    int l = 0,r = 9 + 1;
    while(l + 1 != r){
        int mid = l + (r - l) / 2;
        if(arr[mid] = x){
            return mid;
        }
        else if(x > arr[mid]){
            l = mid;
        }
        else r = mid;
    }
    return -1;
}
int main(){
    cout << binary_search(66);
}

给定两个数组，从A数组中找出B数组中内容，并按升序排序

#include <iostream>
using namespace std;
const int SIZE = 10005;
int arr[SIZE],brr[SIZE];
int binary_search(int x){
    int l = 0,r = 9 + 1;
    while(l + 1 != r){
        int mid = l + (r - l) / 2;
        if(arr[mid] = x){
            return mid;
        }
        else if(x > arr[mid]){
            l = mid;
        }
        else r = mid;
    }
    return 0;
}
int main(){
    int n,m;
    cin >> n >>m;
    for(int i = 1;i <= n;i++){
        cin >> arr[i];
    }
    for(int i = 1;i <= n;i++){
        cin >>brr[i];
    }
    sort(arr + 1,arr + n + 1);
    sort(brr + 1,brr + 1 + n);
    for(int i = 1;i <= m;i++){
        if(binary_search(brr[i])){
            cout << brr[i] << " ";
        }
    }
    return 0;
}