覆盖点集

#include <iostream>
#include <cstdio>
#include <climits>
using namespace std;

int main(){
    int n;
    cin >> n;
    int max_x = INT_MIN,max_y = INT_MIN;
    int min_y = INT_MAX,min_x = INT_MAX;
    for(int i = 0;i < n;i ++){
        int x,y;
        cin >> x >> y;
        if(x == 0 && y == 0) break;
        max_x = max(x,max_x);
        min_x = min(x,min_x);
        max_y = max(y,max_y);
        min_y = min(y,min_y);
    }
    printf("(%d,%d)\n(%d,%d)",min_x,min_y,max_x,max_y);
}

回文串

#include <iostream>
#include <string>
#include <cstdio>
#include <stack>
using namespace std;
//递归
bool is_huiwen1(string str,int start,int end){
    //先设置递归出口，若前面的指针start大于等于后面的指针end时，退出递归
    if(start >= end) return true;
    if(str[start] == str[end]) return is_huiwen1(str,start+1,end-1);
    return false;
}
//栈
bool is_huiwen2(string str){
    stack<char> charstack;
    for(char ch : str){
        charstack.push(ch);
    }
    for(char ch : str){
        if(ch != charstack.top()) return false;
    charstack.pop();
    }
}

int main(){
    string s;
    getline(cin,s);
    if(is_huiwen1(s,0,s.size()-1)) cout << "是回文串" << endl;
    else cout << "bushi" << endl;

    if(is_huiwen2(s)) cout << "是" <<endl;
    else cout <<" no " <<endl;

    return 0;
}

逆序对数量

//暴力解法
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cmath>
using namespace std;

const int N = 100005;

int main(){
    int a[N] ={0};
    int n;
    int num = 0;
    cin >> n;
    for(int i = 0;i < n;i ++){
        cin >> a[i];
    }
    for(int i = 0;i < n;i ++){
        for(int j = i + 1;j < n;j ++){
            if(a[i] > a[j]) num ++;
        }
    }
    cout << num;
}

//归并排序