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// 983. Minimum Cost For Tickets
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
/*
* you have planned some train traveling one year in advance. the days of the
* year in which you will travel are given as an integer array 'days'. each day
* is an integer 1 - 365. train tickets are sold in three different ways: 1 day
* pass sold for 'costs[0]' dollars 7 day pass sold for 'costs[1]' dollars 30
* day pass sold for 'costs[2]' dollars the passes allow that many days of
* consecutive travel. return mininum number of dollars you need to travel every
* day in the given list of days.
*/
#define MIN(a, b, c) \
((a) < (b) ? ((a) < (c) ? (a) : (c)) : ((b) < (c) ? (b) : (c)))
bool find_item(int *days, int days_size, int target) {
int left = 0, right = days_size - 1, mid;
while (left <= right) {
mid = (left + right) / 2;
if (days[mid] == target)
return true;
if (days[mid] > target)
right = mid - 1;
else
left = mid + 1;
}
return false;
}
int mincostTickets(int *days, int days_size, int *costs, int costs_size) {
int arr_size = days[days_size - 1] + 30;
int *dp = calloc(arr_size, sizeof(int));
for (int i = 30; i < arr_size; i++) {
if (find_item(days, days_size, i - 29) == false)
dp[i] = dp[i - 1];
else
dp[i] = MIN(dp[i - 1] + costs[0], dp[i - 7] + costs[i],
dp[i - 30] + costs[2]);
}
int ans = dp[arr_size - 1];
free(dp);
return ans;
}
int main() {
int d1[] = {1, 4, 6, 7, 8, 20},
d2[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 30, 31};
int c1[] = {2, 7, 15};
printf("%d\n", mincostTickets(d1, 6, c1, 3)); // expect: 11
printf("%d\n", mincostTickets(d2, 12, c1, 3)); // expect: 11
}
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