题解 | #MP3光标位置#

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

//使用滑动窗口,分为两种情况，n<=4和n>4两种。
int main() {
    int n;
    string s;
    int win_b = 1; // 表示窗口开始位置
    int pos = 1; //表示光标位置
    int win_e; //表示窗口结束位置，窗口大小为4
    while (cin >> n >> s) {
        if (n <= 4) {
            win_e = n;
            for (int i = 0; i < s.size(); i++) {
                if (s[i] == 'U') {
                    if (pos == 1) {
                        pos = n;
                    } else {
                        pos = pos - 1;
                    }
                } else {
                    if (pos == n) {
                        pos = 1;
                    } else {
                        pos = pos + 1;
                    }
                }
            }
        } else {
            win_e = 4;
            for (int i = 0; i < s.size(); i++) {
                if (s[i] == 'U') {
                    if (pos == win_b) {
                        if ((win_b == 1) && (pos == 1)) {
                            win_b = n - 3;
                            win_e = win_b + 3;
                            pos = n;
                        } else {
                            pos = pos - 1;
                            win_b = win_b - 1;
                            win_e = win_b + 3;
                        }
                    } else {
                        pos = pos - 1;
                    }
                } else {
                    if (pos == win_e) {
                        if ((win_e == n) && (pos == n)) {
                            win_b = 1;
                            win_e = win_b + 3;
                            pos = 1;
                        } else {
                            pos = pos + 1;
                            win_b = win_b + 1;
                            win_e = win_b + 3;
                        }
                    } else {
                        pos = pos + 1;
                    }
                }
            }
        }
        for(int i=win_b;i<=win_e;i++)
        {
            cout<<i<<" ";
        }
        cout<<endl;
        cout<<pos<<endl;
    }
    return 0;
}
// 64 位输出请用 printf("%lld")