题目来自于leetcode双周赛
class Solution {public:vector cellsInRange(string s) {int l1 = s[0], l2 = s[1], r1 = s[3], r2 = s[4];vector res;for (int i = l1; i <= r1; i++) {for (int j = l2; j <= r2; j++) {string x = "";x += char(i);x += char(j);res.push_back(x);}}return res;}};
