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// 2601. Prime Subtraction Operation
#include "leetcode.h"
/*
* given a 0-indexed integer array 'nums' of length 'n'. you can perform the
* following operation as many times as you want: pick an index 'i' that you
* have not picked before, and pick a prime 'p' strictly less than 'nums[i]'
* then subtract 'p' from 'nums[i]'. return true if you can make 'nums' a
* strictly increasing array using the above operation, and false otherwise. a
* strictly increasing array is an array whose each element is strictly greater
* than its precedingelement
*/
bool prime(int n) {
if (n <= 1)
return false;
for (int i = 2; i * i <= n; i++)
if (!(n % i))
return false;
return true;
}
bool primeSubOperation(int *nums, int numsSize) {
for (int i = numsSize - 2; i >= 0; i--) {
if (nums[i] >= nums[i + 1]) {
int diff = nums[i] - nums[i + 1];
diff++;
while (1) {
if (prime(diff))
break;
diff++;
}
if (diff >= nums[i])
return false;
nums[i] -= diff;
}
}
return true;
}
int main() {
int n1[] = {4, 9, 6, 10}, n2[] = {6, 8, 11, 12}, n3[] = {5, 8, 3};
printf("%d\n", primeSubOperation(n1, ARRAY_SIZE(n1))); // expect: 1
printf("%d\n", primeSubOperation(n2, ARRAY_SIZE(n2))); // expect: 1
printf("%d\n", primeSubOperation(n3, ARRAY_SIZE(n3))); // expect: 0
}
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