字符串的展开

https://www.luogu.org/problemnew/show/P1098

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
typedef __int128 lll;
const int N=10000;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,q;
int p1,p2,p3;
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    scanf("%d%d%d",&p1,&p2,&p3);
    string str;
    cin>>str;
    for(int i=0;str[i]!='\0';i++){
        if(i!=0&&str[i]=='-'){
            if(str[i-1]<str[i+1]&&( (isalpha(str[i-1])&&isalpha(str[i+1])) || (isdigit(str[i-1])&&isdigit(str[i+1])) ) ){
                if(p3==1){
                    if(isalpha(str[i-1])&&isalpha(str[i+1])){
                        for(int j=str[i-1]+1;j<str[i+1];j++){
                            for(int k=1;k<=p2;k++){
                                if(p1==1)
                                    printf("%c",j);
                                if(p1==2)
                                    printf("%c",j-32);
                                if(p1==3)
                                    printf("*");
                            }
                        }
                    }else{
                        for(int j=str[i-1]+1;j<str[i+1];j++){
                            for(int k=1;k<=p2;k++){
                                if(p1==1||p1==2)
                                    printf("%c",j);
                                if(p1==3)
                                    printf("*");
                            }
                        }
                    }
                }else{
                    if(isalpha(str[i-1])&&isalpha(str[i+1])){
                        for(int j=str[i+1]-1;j>str[i-1];j--){
                            for(int k=1;k<=p2;k++){
                                if(p1==1)
                                    printf("%c",j);
                                if(p1==2)
                                    printf("%c",j-32);
                                if(p1==3)
                                    printf("*");
                            }
                        }
                    }else{
                        for(int j=str[i-1]+1;j<str[i+1];j++){
                            for(int k=1;k<=p2;k++){
                                if(p1==1||p1==2)
                                    printf("%c",j);
                                if(p1==3)
                                    printf("*");
                            }
                        }
                    }
                }
            }else{
                printf("-");
            }
        }else{
            printf("%c",str[i]);
        }
    }
    //cout << "Hello world!" << endl;
    return 0;
}