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// 2870. Minimum Number of Operations to Make Array Empty
#include "leetcode.h"
/*
* you are given a 0-indexed array 'nums' consisting of positive integers. there
* are two types of operations that you can apply on the array any number of
* times. choose two elements with equal values and delete them from the array.
* choose three elements with equal values and delete them from the array.
* return the minimum number of operations required to make the array empty, or
* -1 if it is not possible.
*/
int minOperations(int *nums, int nums_size) {
int ans = 0, ctr[1000001] = {0};
for (int i = 0; i < nums_size; i++)
ctr[nums[i]]++;
for (int i = 0; i < 1000001; i++) {
if (ctr[i] == 1)
return -1;
if (ctr[i]) {
if (ctr[i] % 3)
ans += ctr[i] / 3 + 1;
else
ans += ctr[i] / 3;
}
}
return ans;
}
int main() {
int n1[] = {2, 3, 3, 2, 2, 4, 2, 3, 4}, n2[] = {2, 1, 2, 2, 3, 3};
printf("%d\n", minOperations(n1, ARRAY_SIZE(n1))); // expect: 4
printf("%d\n", minOperations(n2, ARRAY_SIZE(n2))); // expect: -1
}
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