代码随想录训练营day8|字符串part1

反转字符串

题目链接

class Solution {
public:
    void reverseString(vector<char>& s) {
        // reverse(s.begin(), s.end());
        int l = 0;
        int r = s.size()-1;
        char a;
        while(l < r){
            a = s[l];
            s[l] = s[r];
            s[r]= a;
            l++;
            r--;
        }
    }
};

反转字符串II

题目链接 

class Solution {
public:
    string reverseStr(string s, int k) {
        int l = 0;
        int n = s.length();
        while(l+k <= n){
            reverse(s.begin() + l, s.begin() + l+k);//反转前k字符
            l += 2*k;
        }
        if(l < n){
            reverse(s.begin() + l, s.end());//反转不足k个的字符
        }
        return s;
    }
};

替换数字

题目链接

#include<iostream>
using namespace std;
#include<string>

int main()
{
    string str;
    cin >> str;
    string res;
    for(int i = 0; i < str.length(); i++){
        if(str[i] >= '0' && str[i] <= '9'){
            res.append("number");        
        }
        else{
            res.push_back(str[i]);
        }
    }
    cout<< res;
}