[leetcode]1109. Corporate Flight Bookings

int* corpFlightBookings(int** bookings, int bookingsSize, int* bookingsColSize, int n, int* returnSize){
    int *arr = (int*)malloc(sizeof(int)*n);
    for(int i=0; i<n; i++)
        arr[i] = 0;
    for(int i=0; i<bookingsSize; i++){
        arr[bookings[i][0]-1] += bookings[i][2];
        if(bookings[i][1] < n)
            arr[bookings[i][1]] -= bookings[i][2];
    }
    for(int i=1; i<n; i++)
        arr[i] += arr[i-1];
    *returnSize = n;
    return arr;
}