參考資訊:
https://www.cnblogs.com/grandyang/p/4480780.html
題目:

解答:
int max(int x, int y)
{
return (x > y) ? x : y;
}
int lengthOfLongestSubstring(char *s)
{
int r = 0;
int c0 = 0;
int left = -1;
int hash[128] = {0};
int len = strlen(s);
for (c0 = 0; c0 < 128; c0++) {
hash[c0] = -1;
}
for (c0 = 0; c0 < len; c0++) {
left = max(left, hash[s[c0]]);
hash[s[c0]] = c0;
r = max(r, (c0 - left));
}
return r;
}