https://cs.stackexchange.com/questions/59797/minimizing-cost-of-bus-travel
gnasher729, Jun 21, 2016 at 20:23
retrieved May 30, 2023 07:44:03 EDT
::::
int n = 6;
int dates [n+1] = { 1, 3, 5, 8, 9, 10, infinity };
int ticket [n];
int cost [n+1];

cost [n] = 0;

for i = n-1 downto 0
    cost for 1 day = 2 + cost [i+1]
    let k7 = smallest k where dates [k] ≥ dates [i] + 7
    cost for 7 day = 7 + cost [k7]
    let k30 = smallest k where dates [k] ≥ dates [i] + 30
    cost for 30 days = 25 + cost [k30]

    if cost for 1 day is smallest
        ticket [i] = 1
        cost [i] = cost for 1 day
    else if cost for 7 day is smallest
        ticket [i] = 7
        cost [i] = cost for 7 days
    else
        ticket [i] = 30
        cost [i] = cost for 30 days
    endif