[topcoder]FoxAndChess

http://community.topcoder.com/stat?c=problem_statement&pm=12725&rd=15702

这题比较简单。首先所有的LR的顺序要一致，二来L和L，R和R的位置有限制关系。

#include <string>
using namespace std;

class FoxAndChess {
public:
    string ableToMove(string begin, string target);
};

string FoxAndChess::ableToMove(string begin, string target) {
    int i = 0;
    int j = 0;
    int len = begin.length();
    while (i < len && j < len) {
        while (i < len && begin[i] == '.') i++;
        while (j < len && target[j] == '.') j++;
        if (i == len && j == len) break;
        if (i == len || j == len) return "Impossible";
        if (begin[i] != target[j]) return "Impossible";
        if ((begin[i] == 'L' && i < j) ||
            (begin[i] == 'R' && i > j)) return "Impossible";
        i++; j++;
    }
    return "Possible";
};