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// 2369. Check if There is a Valid Partition For The Array
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
/*
* given a 0-indexed integer array 'nums', you have to partition the array into
* one or more contiguous subarrays. we call a partition of the array valid if
* each of the obtained subarrays satisfies one of the following conditions
* - the subarray consists of exactly 2 equal elements. for example, the
* subarray '[2,2]' is good.
* - the subarray consists of exactly 3 equal elements. for example, the
* subarray '[4,4,4]' is good.
* - the subarray consists of exactly 3 consecutive increasing elements, that
* is, the difference between adjacent elements is 1. for example, the subarray
* '[3,4,5]' is good, but the subarray '[1,3,5]' is not. return true if the
* array has at least one valid partition. otherwise, return false.
*/
bool validPartition(int *nums, int nums_size) {
int n = nums_size, *dp = calloc(n + 1, sizeof(bool));
dp[0] = true;
if (nums[0] == nums[1])
dp[2] = true;
int consecutive_false = 0;
for (int i = 3; i <= n; i++) {
if (nums[i - 1] == nums[i - 2]) {
dp[i] |= dp[i - 2];
if (dp[i]) {
consecutive_false = 0;
continue;
}
if (nums[i - 2] == nums[i - 3]) {
dp[i] |= dp[i - 3];
if (dp[i]) {
consecutive_false = 0;
continue;
}
}
} else {
if ((nums[i - 1] == nums[i - 2] + 1) &&
(nums[i - 2] == nums[i - 3] + 1)) {
dp[i] |= dp[i - 3];
if (dp[i]) {
consecutive_false = 0;
continue;
}
}
}
consecutive_false++;
if (consecutive_false == 3)
break;
}
return dp[n];
}
int main() {
int n1[] = {4, 4, 4, 5, 6}, n2[] = {1, 1, 1, 2};
printf("%d\n", validPartition(n1, 5)); // expect: 1
printf("%d\n", validPartition(n2, 4)); // expect: 0
}
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