// 3208. alternating groups ii #include "leetcode.h" /* * there is a circle of red and blue tiles. you are given an array of integers * 'colours' and an integer 'k'. the colour of tile 'i' is represented by * 'colours[i]': '0' means that tile 'i' is red, and '1' means that tile 'i' is * blue. an alternating group is every 'k' contiguous tiles in the circle with * alternating colours. return the number of alternating groups. note that since * 'colours' represents a circle, the first and last tiles are considered to be * next to eachother. */ int numberOfAlternatingGroups(int *colours, int coloursSize, int k) { int cnt = 0, left = 0; for (int right = 0; right < coloursSize + k - 1; ++right) { if (right && colours[right % coloursSize] == colours[(right - 1) % coloursSize]) left = right; if (right - left + 1 >= k) cnt++; } return cnt; } int main() { int c1[] = {0, 1, 0, 1, 0}, c2[] = {0, 1, 0, 0, 1, 0, 1}, c3[] = {1, 1, 0, 1}; printf("%d\n", numberOfAlternatingGroups(c1, ARRAY_SIZE(c1), 3)); // expect: 3 printf("%d\n", numberOfAlternatingGroups(c2, ARRAY_SIZE(c2), 6)); // expect: 2 printf("%d\n", numberOfAlternatingGroups(c3, ARRAY_SIZE(c3), 4)); // expect: 0 }