题解 | 字符串排序

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;


struct ch {
	char c;
	int seq;
};

bool compare(ch lhs, ch rhs) {
	if (tolower(lhs.c) < tolower(rhs.c)) {
		return true;
	}
	else if (tolower(lhs.c) == tolower(rhs.c) && lhs.seq < rhs.seq) {
		return true;
	}
	else {
		return false;
	}
}

int main() {
	string s;
	while (getline(cin, s)) {
		vector<ch> str;
		set<int> isletter;
		for (int i = 0; i < s.size(); i++) {
			if ((s[i] >= 'A' && s[i] <= 'Z') || (s[i] >= 'a' && s[i] <= 'z')) {
				ch x;
				x.c = s[i];
				x.seq = i;
				isletter.insert(i);
				str.push_back(x);
			}
		}
		sort(str.begin(), str.end(), compare);
		int j = 0;
		for (int i = 0; i < s.size(); i++) {
			if (isletter.find(i) != isletter.end()) {
				s[i] = str[j].c;
				j++;
			}
		}
		cout << s << endl;
	}
}