'''

class Solution {

public:

int lengthOfLongestSubstring(string s) {

int len = s.length();

int m[256];

memset(m, -1, sizeof(m));

int i = 0, start = 0;;

int maxL = 0;

while(i < len){

if(m[s[i]] == -1){

m[s[i]] = i;

}

else{

maxL = max(maxL, i - start);

int tmp = start;

start = m[s[i]] + 1;

for(int k = tmp; k < start; ++k)

m[s[k]] = -1;

m[s[i]] = i;

}

++i;

}

maxL = max(maxL, i - start);

return maxL;

}

};

''''