// 976. Largest Perimeter Triangle #include "leetcode.h" /* * given an integer array 'nums', return the largest perimeter of a triangle * with a non-zero area, formed from three of these lengths. if it is impossible * to form any triangle of a non-zero area, return 0. */ int cmp(const void *a, const void *b) { return (*(int *)a - *(int *)b); } int largestPerimeter(int *nums, int numsSize) { qsort(nums, numsSize, sizeof(int), cmp); for (int i = numsSize - 3; i >= 0; i--) if (nums[i] < nums[i - 1] + nums[i - 2]) return nums[i] + nums[i] + nums[i - 2]; return 0; } int main() { int n1[] = {2, 1, 2}, n2[] = {3, 2, 3, 4}; printf("%d\n", largestPerimeter(n1, ARRAY_SIZE(n1))); // expect: 5 printf("%d\n", largestPerimeter(n2, ARRAY_SIZE(n2))); // expect: 0 }