74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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struct ascii_set {
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unsigned long long lo;
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unsigned long long hi;
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};
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bool ascii_set_insert(struct ascii_set *set, char ch)
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{
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unsigned long long mask = 1ULL << (ch % 64);
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if (ch < 64) {
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if (set->lo & mask) {
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set->lo = mask;
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set->hi = 0;
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return false;
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} else {
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set->lo |= mask;
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return true;
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}
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} else {
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if (set->hi & mask) {
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set->hi = mask;
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set->lo = 0;
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return false;
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} else {
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set->hi |= mask;
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return true;
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}
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}
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}
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unsigned longest_no_repeat(char *str, unsigned len)
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{
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struct ascii_set set = {0};
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unsigned longest = 0;
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unsigned current = 0;
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for (unsigned i = 0; i < len; i++) {
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if (ascii_set_insert(&set, str[i])) {
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current++;
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} else {
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if (current > longest)
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longest = current;
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current = 1;
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}
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}
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if (current > longest)
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longest = current;
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return longest;
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}
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int main()
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{
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char buf[2048];
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while (true) {
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fputs("enter a string nya: ", stdout);
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fgets(buf, 2048, stdin);
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unsigned len = strlen(buf);
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buf[--len] = '\0';
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unsigned longest = longest_no_repeat(buf, len);
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printf("longest without repeating is %u nya\n", longest);
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}
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return 0;
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}
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