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// 2434. Using a Robot to Print the Lexicographically Smallest String
#include "leetcode.h"
/*
* you are given a string 's' and a robot that currently holds an empty string
* 't'. apply one of the followiing operations until 's' and 't' are both empty.
* remove the first character of a string 's' and give it to the robot. the
* robot will append this charcter to the string 't'. remove the last character
* of a string 't' and give it to the robot. the robot will write this character
* on paper.
*/
char *robotWithString(char *s) {
int n = strlen(s), a_idx = 0, t_idx = 0, min_idx = 0, begin = 0;
char *ans = (char *)malloc((n + 1) * sizeof(char));
ans[n] = '\0';
char *t = (char *)malloc(n * sizeof(char)), low = 'a';
while (begin < n) {
char min = s[begin];
min_idx = begin;
for (int i = begin; i < n; i++) {
if (s[i] == low) {
min_idx = i;
min = low;
break;
} else if (s[i] < min) {
min = s[i];
min_idx = i;
}
}
low = s[min_idx];
if (!t_idx) {
ans[a_idx++] = low;
for (int j = begin; j < min_idx; j++)
t[t_idx++] = s[j];
} else {
while (t_idx >= 0) {
if (t_idx > 0 && t[t_idx - 1] <= s[min_idx])
ans[a_idx++] = t[t_idx-- - 1];
else {
ans[a_idx++] = s[min_idx];
for (int j = begin; j < min_idx; j++)
t[t_idx++] = s[j];
break;
}
}
}
begin = min_idx + 1;
}
for (int i = t_idx - 1; i >= 0; i--)
ans[a_idx++] = t[i];
free(t);
return ans;
}
int main() {
char *s1 = "zza", *s2 = "bac", *s3 = "bdda";
char *rws1 = robotWithString(s1);
char *rws2 = robotWithString(s2);
char *rws3 = robotWithString(s3);
printf("%s\n", rws1); // expect: azz
printf("%s\n", rws2); // expect: abc
printf("%s\n", rws3); // expect: addb
free(rws1);
free(rws2);
free(rws3);
}
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