3.Longest Substring Without Repeating Characters

 1 #include <stdlib.h>
 2 #include <stdio.h>
 3 #include <string>
 4 #include <string.h>
 5 #include <iostream>
 6 #include <vector>
 7 using namespace std;
 8 #define debug(x) cout << #x << " at line " << __LINE__ << " is: " << x << endl
 9 int max(int a, int b){
10     return (a>b?a:b);
11 }
12 
13 int lengthOfLongestSubstring(char* s) {
14     int sidx = 0;
15     int MAXLEN = 0;
16 
17     while (s[sidx] != ‘\0‘){
18         ++sidx;
19     }
20     //cout << sidx << ‘\n‘;
21 
22     for (int k = 0; k < sidx; ++k) {
23 
24         int HASHMAP[128];
25         memset(HASHMAP, 0x00, sizeof(HASHMAP));
26         HASHMAP[s[k]] = 1;
27         //debug("*******");debug(k);debug(s[k]);debug("*******");
28         //MAXLEN = 1;
29         //left
30         int llen = 0;
31         for (int i = k-1; i >= 0; ++i) {
32             if(HASHMAP[s[i]] == 0){
33                 ++llen;
34                 //debug(llen);debug(i);debug(s[i]);
35                 HASHMAP[s[i]] = 1;
36             }else if (HASHMAP[s[i]] == 1) {
37                 break;
38             }
39         }
40         //right
41         int rlen = 0;
42         for (int j = k+1; j < sidx; ++j) {
43             if(HASHMAP[s[j]] == 0){
44                 ++rlen;
45                 //debug(rlen);debug(j);debug(s[j]);
46                 HASHMAP[s[j]] = 1;
47             }else if (HASHMAP[s[j]] == 1) {
48                 break;
49             }
50         }
51 
52         if(MAXLEN < (llen + rlen+1)){
53             MAXLEN = llen + rlen+1;
54         }
55         //debug(MAXLEN);
56 
57     }
58 
59     return MAXLEN;
60 }
61 int main(void) {
62     //freopen("../in.txt", "r", stdin);
63     char a[1024];
64     memset(a, 0x00, sizeof(a));
65     scanf("%s", a);
66     getchar();
67     //cout << a << endl;
68     printf("%d\n", lengthOfLongestSubstring(a));
69 
70     return 0;
71 }