【力扣 中等 C】983. 最低票价

目录

题目

解法一：一维dp

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题目

待添加

解法一：一维dp

int min(int a, int b)
{
    return a < b ? a : b;
}

int find(const int* nums, int start, int end, int target)
{
    int left = start, right = end;
    int index = end + 1;
    while (left <= right)
    {
        int mid = (left + right) / 2;
        if (nums[mid] < target)
            left = mid + 1;
        else if (nums[mid] > target)
        {
            index = mid;
            right = mid - 1;
        }
        else
            return mid;
    }
    return index;
}
 
int compute(const int* days, int size1, const int* costs, int size2)
{
    const int cDays[3] = {1, 7, 30};

    int* dp = malloc(sizeof(*dp) * (size1 + 1));
    for (int i = 0; i < size1; i++)
        dp[i] = INT_MAX;
    dp[size1] = 0;

    for (int i = size1 - 1; i >= 0; i--)
        for (int j = 0; j < 3; j++)
        {
            int nextIndex = find(days, i, size1 - 1, days[i] + cDays[j]);
            dp[i] = min(dp[i], costs[j] + dp[nextIndex]);
        }
    
    int minCharge = dp[0];
    free(dp);
    return minCharge;
}
 
int mincostTickets(int* days, int daysSize, int* costs, int costsSize)
{
    return compute(days, daysSize, costs, costsSize);
}