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// 1539. Kth Missing Positive Number
#include <stdio.h>
/*
* given array 'arr' of positive integers sorted in a strictly increasing order,
* and an integer 'k', return 'kth' positive integer missing from array -- o(log
* n)
*/
int findKthPositive(int *arr, int arr_size, int k) {
int l = 0, r = arr_size, m;
while (l < r) {
m = (l + r) / 2;
if (arr[m] - 1 - m < k)
l = m + 1;
else
r = m;
}
return l + k;
}
int main() {
int a1[] = {2, 3, 4, 7, 11}, a2[] = {1, 2, 3, 4};
printf("%d\n", findKthPositive(a1, 5, 5)); // expect: 9
printf("%d\n", findKthPositive(a2, 2, 4)); // expect: 6
}
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