1208

class Solution {
public:
    int equalSubstring(string s, string t, int maxCost) {
        int ans = 0, left, right;

        for(left=0, right=0; right<s.length(); right++){
            maxCost -= abs(s[right]-t[right]);
            while(maxCost < 0) {
                maxCost += abs(s[left]-t[left]);
                left++;
            }
            ans = max(ans, right-left+1);
        }
        return ans;
    }
};