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// 1079. Letter Tile Possibilities
#include "leetcode.h"
/*
* given 'n' tiles where each tile has one letter ('tiles[i]') printed on it.
* return the number of possible non-empty letters printed on those tiles.
*/
void dfs(int *alpha, int *sum) {
for (int i = 0; i < 26; i++) {
if (!alpha[i])
continue;
(*sum)++;
alpha[i]--;
dfs(alpha, sum);
alpha[i]++;
}
}
int numTilePossibilities(char *tiles) {
int *alpha = calloc(26, sizeof(int));
for (int i = 0; i < strlen(tiles); i++)
alpha[tiles[i] - 'A']++;
int ans = 0;
dfs(alpha, &ans);
free(alpha);
return ans;
}
int main() {
char *t1 = "AAB", *t2 = "AAABBC", *t3 = "V";
printf("%d\n", numTilePossibilities(t1)); // expect: 8
printf("%d\n", numTilePossibilities(t2)); // expect: 188
printf("%d\n", numTilePossibilities(t3)); // expect: 1
}
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