// 75. Sort Colors #include "leetcode.h" /* * given an array 'nums' with 'n' objects coloured red, white, or blue, sort * them in place so that objects of the same colour are adjacent with the * colours in the order red, white and blue. we will use the integer 0,1,2 to * represent the colour red, white, and blue respecitvely. you must solve this * problem without the library's sort function. */ void sortColors(int *nums, int numsSize) { int two_ptr = numsSize - 1, zero_ptr = 0, one_ptr = 0; while (one_ptr <= two_ptr) { if (!nums[one_ptr]) { int tmp = nums[zero_ptr]; nums[zero_ptr] = nums[one_ptr]; nums[one_ptr] = tmp; one_ptr++; zero_ptr++; } else if (nums[one_ptr] == 1) one_ptr++; else { int tmp = nums[two_ptr]; nums[two_ptr] = nums[one_ptr]; nums[one_ptr] = tmp; two_ptr--; } } } int main() { int n1[] = {2, 0, 2, 1, 1, 0}, n2[] = {2, 0, 1}; sortColors(n1, ARRAY_SIZE(n1)); sortColors(n2, ARRAY_SIZE(n2)); for (int i = 0; i < ARRAY_SIZE(n1); i++) printf("%d ", n1[i]); printf("\n"); for (int i = 0; i < ARRAY_SIZE(n2); i++) printf("%d ", n2[i]); printf("\n"); }