src2.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int max(int a, int b)
{
	return a >= b ? a : b;
}
int lengthOfLongestSubstring(char *s) {
	int hash[256],len = strlen(s), i;
	int result = 0, curLen = 0, pos = 0,maxPos;
	if (len < 2)
		return len;
	memset(hash, -1, sizeof(hash));
	for (i = 0; i < len; ++i) {
		if (hash[s[i]] == -1) {
			curLen++;
			hash[s[i]] = i;
		} else {
			result = max(result, curLen); // update result
			maxPos = max(pos, hash[s[i]]);
			curLen = i - maxPos;
			pos = maxPos;
			hash[s[i]] = i;
		}
	}
	return result >= curLen ? result : curLen;
}
int main(int argc, char **argv)
{
	char s1[] = "abba";
	char s2[] = "abca";
	char s3[] = "abcb";
	char s4[] = "pwwkew";
	char s5[] = "tmmzuxt";
	char s6[] = "aa";
	//printf("%d\n", lengthOfLongestSubstring(s1));
	//printf("%d\n", lengthOfLongestSubstring(s2));
	//printf("%d\n", lengthOfLongestSubstring(s3));
	printf("%d\n", lengthOfLongestSubstring(s4));
	printf("%d\n", lengthOfLongestSubstring(s5));
	printf("%d\n", lengthOfLongestSubstring(s6));
	return 0;
}