my-solutions/problems/3-longest-substring/lib.c

59 lines
1.5 KiB
C

#include <string.h>
#include "lib.h"
void resetArray(int* count) {
int length = '~' - 32 + 1;
for (int i=0; i<length; i++) {
count[i] = 0;
}
}
int lengthOfLongestSubstring(char * s) {
// Create an array to count every symbol
// '~' is one of the last symbols in ascii table (except DEL)
int count['~' - 32 + 1];
resetArray(count);
int len = strlen(s);
// Start of the current sequence
int start = 0;
// Result will be stored here
int maxlen = 0;
while (start < len) {
// End of the current sequence
int end = start;
while (end < len) {
// Calculate index in array
int ch = s[end] - 32;
// Symbol repeated
if (count[ch] == 1) {
// Fill array with 0
resetArray(count);
// Save max length
int newmaxlen = end - start;
if (newmaxlen > maxlen)
maxlen = newmaxlen;
// Move to the next sequence
start++;
end = start;
}
else {
// Save the symbol
count[ch]++;
// Move to the next symbol
end++;
}
}
// Save max length
int newmaxlen = end - start;
if (newmaxlen > maxlen)
maxlen = newmaxlen;
// Move to the next sequence
start++;
end = start;
}
return maxlen;
}