// 2110. Number of Smooth Descent Periods of a Stock #include "leetcode.h" /* * you are given an integer array 'prices' representing the daily price history * of a stock where 'prices[i]' is the stock price on the i'th day. a smooth * descent period of a stock consists of one or more contiguous days such that * the price on each day is lower than the price on the peceding day by * exactly 1. the first day of the period is exempted from this rule. return the * number of smooth descent periods. */ long long getDescentPeriods(int *prices, int pricesSize) { int *dp = (int *)malloc(pricesSize * sizeof(int)); dp[0] = 1; long long ans = 1; for (int i = 1; i < pricesSize; i++) { dp[i] = prices[i] == prices[i - 1] - 1 ? dp[i - 1] + 1 : 1; ans += dp[i]; } free(dp); return ans; } int main() { int p1[] = {3, 2, 1, 4}, p2[] = {8, 6, 7, 7}, p3[] = {1}; printf("%lld\n", getDescentPeriods(p1, ARRAY_SIZE(p1))); // expect: 7 printf("%lld\n", getDescentPeriods(p2, ARRAY_SIZE(p2))); // expect: 4 printf("%lld\n", getDescentPeriods(p3, ARRAY_SIZE(p3))); // expect: 1 }