题解

用深搜写的

#include <iostream>
#include <cstdio>
using namespace std;
char a[105];
bool vis[105];
int n;
int f[55][2];
bool dfs(int ct){
	if(ct == n / 2 + 1){
		for(int i = 1; i <= n / 2; i++){
			cout << f[i][0] << ' ' << f[i][1] << endl;
		}
		return 1;
	}
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= n; j++){
			if(abs(i - j) > 1 && !vis[i] && !vis[j] && (a[i] == 'L' || a[j] == 'R')){
				vis[i] = vis[j] = 1;
				f[ct][0] = i, f[ct][1] = j;
				if(dfs(ct + 1)) return 1;
				vis[i] = vis[j] = 0;
			}
		}
	}return 0;
}
int main(){
	cin >> n;
	cin >> a + 1;
	dfs(1);
}