Longest Substring Without Repeating Characters
Given a string, find the length of the longest substring
without repeating characters.
Examples:
Given "abcabcbb", the answer is "abc", which the length is 3.
Given "bbbbb", the answer is "b", with the length of 1.
Given "pwwkew", the answer is "wke", with the length of 3.
Note that the answer must be a substring,
"pwke" is a subsequence and not a substring.
1 /************************************************************************* 2 > File Name: LeetCode003.c 3 > Author: Juntaran 4 > Mail: JuntaranMail@gmail.com 5 > Created Time: Tue 17 May 2016 17:10:02 PM CST 6 ************************************************************************/ 7 8 /************************************************************************* 9 10 Longest Substring Without Repeating Characters 11 12 Given a string, find the length of the longest substring 13 without repeating characters. 14 15 Examples: 16 17 Given "abcabcbb", the answer is "abc", which the length is 3. 18 19 Given "bbbbb", the answer is "b", with the length of 1. 20 21 Given "pwwkew", the answer is "wke", with the length of 3. 22 Note that the answer must be a substring, 23 "pwke" is a subsequence and not a substring. 24 25 ************************************************************************/ 26 27 #include "stdio.h" 28 29 /* 8ms */ 30 int lengthOfLongestSubstring(char* s) 31 { 32 int n = strlen(s); 33 34 if( n <= 1 ) 35 { 36 return n; 37 } 38 39 int i = 0, j = 0; 40 int maxLen = 0; 41 int exist[256] = { 0 }; 42 while( j < n ) 43 { 44 if( exist[s[j]] ) 45 { 46 maxLen = maxLen>(j-i) ? maxLen : (j-i); 47 while( s[i] != s[j] ) 48 { 49 exist[s[i]] = 0; 50 i++; 51 } 52 i++; 53 j++; 54 } 55 else 56 { 57 exist[s[j]] = 1; 58 j++; 59 } 60 } 61 maxLen = maxLen>(n-i) ? maxLen : (n-i); 62 return maxLen; 63 } 64 65 /* 36ms */ 66 int lengthOfLongestSubstring2(char* s) 67 { 68 int len = 0; 69 int p=0 , q=0, i; 70 71 for( q=0; q<strlen(s); q++ ) 72 { 73 for( i=p; i<q; i++ ) 74 { 75 if( s[q] == s[i] ) 76 { 77 if( q-p > len ) len = q-p; 78 p = i+1; 79 } 80 } 81 } 82 len = len>q-p?len:q-p; 83 return len; 84 } 85 86 int main() 87 { 88 char* s = "abccab"; 89 int ret = lengthOfLongestSubstring(s); 90 printf("%d ", ret); 91 92 return 0; 93 }