1 typedef long long ll;
 2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 3 #define _rep(i,a,b) for(int i = (a);i > b;i --)
 4 #define INF 0x3f3f3f3f
 5 #define pb push_back
 6 #define maxn 10000
 7 
 8 class Solution
 9 {
10     public:
11         vector<int> d;
12         int equalSubstring(string s, string t, int maxCost)
13         {
14             int ans = 0;
15             _for(i,0,s.size())
16             {
17                 if(s[i]>t[i])
18                     d.pb(s[i]-t[i]);
19                 else
20                     d.pb(t[i]-s[i]);
21             }
22             int st = 0,ed = 0;
23             int sum = 0;
24             while(ed < d.size() && st<=ed)
25             {
26                 sum += d[ed];
27                 if(sum <= maxCost)
28                 {
29                     ans = max(ans,ed-st+1);
30                     ed ++;
31                 }
32                 else
33                 {
34                     sum -= d[st];
35                     st ++;
36                     ed ++;
37                 }
38             }
39             return ans;
40         }
41 };